Relationship Anxiety: The Everyday Symptoms and How to Tell Fear From a Real Warning

Persistent fear that a relationship is ending, or was never real to begin with, shows up in behavior and in the body long before it reaches words. This guide covers the everyday symptoms, the physical signs, the reason reassurance stops working, and the practical tests that separate an anxiety response from an accurate warning about your partner.

What is relationship anxiety, and what does it feel like day to day?

Relationship anxiety is persistent fear about the security of a romantic relationship that keeps running when nothing has gone wrong, and day to day it feels less like sadness than like low-grade vigilance. The clinical vocabulary has no single diagnosis for it, and neither the DSM-5 nor the ICD-11 lists anything under that name. What people mean by the phrase is a cluster: doubt about whether a partner really wants them, doubt about whether they really want the partner, and a monitoring habit that treats every ordinary variation in a partner's mood as data. Mornings are often the quietest part. The fear tends to arrive attached to something specific, a shorter text than usual, a cancelled plan, a friend's breakup, and then it stays long past the point where the trigger itself has been settled. People describe a split screen. One track handles the day. The other runs a background process that keeps asking whether the relationship is still intact, and that track consumes attention you would otherwise spend on work, friends, or the person in front of you. The feeling is rarely dramatic. It is repetitive, and it is tiring, and most people carrying it can hold an ordinary conversation while it runs.

The phrase relationship anxiety belongs to popular psychology rather than to any diagnostic manual, which is why definitions vary so widely between sources. Clinicians tend to sort the same experiences into existing categories instead. Some of it fits generalized anxiety, where the worry topic happens to be a partner this year and a job the year before. Some fits panic, where the body fires first and the relationship supplies an explanation afterward. Some fits the pattern the obsessive-compulsive literature calls relationship OCD, in which doubt about a partner behaves like a compulsion loop rather than like ordinary worry, though that label is a research and clinical shorthand rather than a separate diagnosis. A large share of it is a learned expectation about closeness, which psychology files under attachment. For that mechanism, including where an anxious pattern comes from and whether it changes, see Attachment Styles: The Four Types and How They Show Up in Relationships. This article stays at the level of recognition: what the thing looks like from the inside, what it looks like from across the room, and which of the two views to trust when they disagree.

Is relationship anxiety the same thing as anxious attachment?

No. Anxious attachment is one common source of relationship anxiety, and relationship anxiety also appears in people whose pattern was secure until something specific happened, such as an affair, a sudden abandonment, or a partner who is genuinely inconsistent. Treating the two as identical sends people looking inward for a cause that is sometimes sitting across the table from them.

How is relationship anxiety different from ordinary worry about a partner?

Ordinary worry attaches to a real problem, produces a decision or a conversation, and then stops. Relationship anxiety survives the answer. You can get exactly the reassurance you asked for, feel better for an hour, and find the doubt reassembled by evening with a fresh supporting detail attached to it. Duration and repetition separate the two far more reliably than intensity does.

Can you have relationship anxiety and still be happy in the relationship?

Yes, and most people who have it are. The two run in parallel rather than cancelling each other out. Someone can enjoy a weekend completely, mean everything they said during it, and still spend Sunday night rehearsing how the relationship ends. Real affection does not disprove the anxiety, and the anxiety does not disprove the affection.

What behaviors are signs of relationship anxiety?

The behavioral signs of relationship anxiety cluster into four habits: checking, testing, over-adjusting, and pre-emptive withdrawal. Checking is the most visible one. Rereading messages for tone, counting the minutes to a reply, scrolling a partner's activity to confirm they are alive and not upset, asking some version of are we okay several times a week. Testing is quieter and much less obvious to the person doing it: going silent to see whether the partner notices, mentioning an ex to watch the reaction, refusing an offer of help to find out whether it gets repeated. Over-adjusting means editing yourself down. Opinions get softened, plans get agreed to that you do not want, complaints get postponed indefinitely, and the relationship starts running on a version of you that is cheaper to maintain. Pre-emptive withdrawal is the one that gets misread as coldness. When the fear peaks, some people pick a fight, some go quiet for a day, and a few end the relationship outright, because ending it yourself is the only version of the loss you control. Any one of these can be a bad week. The pattern is the sign.

What makes these behaviors hard to see from the inside is that each produces immediate relief, which is the exact shape of a habit that keeps itself alive. The check answers the question, the anxiety drops, and the drop teaches the brain that checking is what fixed it. Exposure-based cognitive behavioral treatment works the opposite way: tolerating the uncertainty without the check, so the drop happens on its own and stops being credited to the ritual. Two of the four also carry a cost the person rarely counts. Over-adjusting removes the information a partner needs to meet you at all, so the relationship gets safer and less real at the same time. Testing produces an answer you cannot use, because a partner who passes a test they did not know they were sitting has proved nothing you can hold. Pre-emptive withdrawal is the costliest of the four, since it is the only one that can end the relationship on its own. For the belief sitting under the editing, see Limiting Beliefs: How to Identify Them and Replace Them.

Is checking my partner's location or messages a sign of relationship anxiety?

Usually yes, though the function matters more than the label. Checking driven by anxiety aims at relief and repeats regardless of what it finds, since clean results reassure for a few hours and ambiguous ones start a fresh search. Location sharing that both people agreed to openly, for a stated reason, behaves differently. Secrecy is the reliable warning sign here.

Why do I start fights when I feel most insecure?

A fight restores contact. Distance and silence are the intolerable states, and conflict at least guarantees that a partner is engaged and paying full attention, which is why the argument itself often feels better than the hour before it. The subject is usually incidental, and that is a useful clue: if you cannot remember by morning what it was about, it was about proximity.

Does relationship anxiety make people end relationships they want to keep?

It does, and the move has its own logic. Ending it yourself converts an unbearable uncertainty into a certain loss you chose, and the relief in the first two days is genuine. It commonly reverses within a week, once the threat is gone and the affection is still sitting there. Repeated breakups and reconciliations are among the clearest behavioral signatures.

What are the physical symptoms of relationship anxiety?

The physical symptoms of relationship anxiety are the ordinary symptoms of sympathetic nervous system arousal delivered on a relationship trigger: a tight band across the chest, a stomach that drops or churns, a throat that feels narrowed, fast shallow breathing, cold hands, a jaw that has been clenched all afternoon. Sleep is where most people notice it first. The fear arrives at the point where distraction stops, so falling asleep takes an hour, and waking at three or four with the whole argument already assembled is common. Appetite goes in either direction. Many people lose it entirely on the days a relationship feels uncertain, and some eat continuously for the same reason. The same arousal produces symptoms nobody connects to a partner: a low headache behind the eyes, shoulders held near the ears, a flush of heat when a phone buzzes, an urgent need for the bathroom before a difficult conversation. Chest pain, breathlessness and a racing heart are also symptoms of cardiac and thyroid conditions. Get new or severe symptoms of that kind assessed by a clinician rather than assuming you know the cause.

Timing tells you more than the sensation does. Anxiety-driven symptoms are usually anticipatory, arriving before the conversation rather than during it, and they resolve within an hour or two of the uncertainty ending. Symptoms that persist for weeks regardless of what the relationship is doing, or that wake you from sleep, belong in a conversation with a doctor instead. The body also keeps a longer record than the mind will admit to. People who describe their relationship as fine often report a permanently tight upper back, unexplained nausea on Sunday evenings, or a startle response to a notification sound. Read those as data about the relationship rather than as a posture problem. Energy-system traditions map the same sensations onto specific centers, chest tightness to the heart, throat constriction to the throat, stomach churn to the solar plexus. For that reading, see Chakra Blockage Symptoms: How to Know Which Chakra Is Blocked. The two accounts are not interchangeable. Muscle tension and breathing rate can be measured and a blocked center cannot, so where they conflict the physiological reading is the one that survives a test.

Why does my chest get tight when my partner is distant?

Chest tightness under stress comes from the muscles between the ribs and the diaphragm bracing, plus a shift into shallow upper-chest breathing that leaves the ribcage held high. Anxious chest tightness is usually muscular rather than cardiac, which is why it tends to ease on a long exhale and worsen with breath-holding. That is a general pattern rather than a test you can run on yourself. Chest pain that is severe, persistent, or brought on by exertion still needs medical assessment first.

Can relationship anxiety cause stomach problems?

Yes. The gut carries its own dense nerve supply and responds directly to stress signaling, which is why nausea, cramping, loose stools and appetite loss track relationship stress so closely. Symptoms that continue after the stressful stretch has ended, or that come with blood, unexplained weight loss or fever, need a doctor rather than another reassurance conversation.

How do I calm my body down before a difficult conversation?

Lengthen the exhale before you say anything at all. Slow breathing with an exhale longer than the inhale shifts the balance toward parasympathetic activity, and a body that has come down two notches can hear an answer it would otherwise have argued with. For the actual protocols, including the physiological sigh and safe practice, see Breathwork: Techniques, Effects and How to Start Safely.

How do you tell relationship anxiety from a real warning sign about your partner?

What separates relationship anxiety from an accurate warning about a partner is whether the feeling is generated by evidence or by the absence of it. Anxiety runs hardest on ambiguity: an unanswered message, a flat tone, a partner who is simply tired. An accurate warning tends to arrive with specifics you could write down, dated, repeatable, and noticeable to someone who is not in love with the person. Four questions do most of the work. First, can you name the behavior without naming the feeling? He was distant on Tuesday and I panicked is a feeling. He has cancelled four of the last six plans and got irritated when I asked about it is a behavior. Second, does the fear predate this partner? A doubt that ran identically through your last two relationships is telling you about you. Third, does information calm it? A real concern is answerable and then stays answered. Fourth, what do the people who know you both actually say? Anxiety usually contradicts every outside observer, and an accurate warning usually collects quiet corroboration. Both can be true at once. Anxious people also get cheated on.

The difference between anxiety and intuition is not that intuition feels calmer. Both arrive as dread. The workable distinction is that intuition points and anxiety circles. Intuition tends to be specific and singular, attaches to one moment, and does not need re-running every night, while anxiety generalizes, produces a hundred hypotheses, and rewrites the same scene endlessly with new endings. Writing it down is the cheapest diagnostic available. Keep a plain log of the trigger, the time, what actually happened and what you predicted would happen. After a month the log answers the question for you, because either the predictions came true or they did not, and either the incidents accumulate into a pattern or they turn out to have been one evening remembered forty times. Some warnings need no such test. Monitoring, isolation from friends, financial control and intimidation are unambiguous, and they are not what this article means by anxiety. A useful cross-check is to describe the situation to a friend in behavior only, with the feelings left out, and see what they say back. Anxiety tends to sound thin once the adjectives are removed, while a real pattern tends to sound worse.

How can I tell relationship anxiety from intuition?

Ask what the feeling wants you to do. Intuition asks you to look at something specific, and it usually survives being written down and checked later. Anxiety asks you for reassurance and cannot be settled by any answer. Track both for a few weeks before acting, because an intuition that keeps pointing at the same concrete thing deserves a conversation rather than dismissal.

What behaviors count as real warning signs rather than my anxiety?

Behavior that would concern a neutral observer: repeated lying, contempt in ordinary conversation, monitoring your phone or location, controlling the money, pressuring you away from friends and family, threats, and any physical intimidation. These are not calibration problems. If you recognize several of them, talk to someone outside the relationship, including a domestic abuse service in your country.

Should I trust a gut feeling that my partner is cheating?

Treat it as a question rather than a verdict. Gut feelings about infidelity are sometimes accurate and often wrong, and the same certainty accompanies both. Name the specific observations behind it, ask directly instead of investigating covertly, and watch whether the feeling settles after a straight answer. A suspicion that survives every answer is usually about uncertainty itself.

Why does relationship anxiety often get louder when the relationship is going well?

Relationship anxiety usually intensifies when things are going well because a good relationship is what makes the loss worth fearing. While the outcome is still uncertain, some part of the mind is holding back. Once the person matters, and once you have said so out loud, the exposure is real, and the alarm system starts working on the thing there is now something to lose. Specific milestones set it off with remarkable consistency: saying it first, meeting the family, moving in, a proposal, a pregnancy. Each one closes an exit. People who felt fine through six months of ambiguity often fall apart in the week after a partner finally commits, which confuses everyone involved and reads as sabotage from the outside. There is a second mechanism. Calm is unfamiliar. Someone whose earlier relationships ran on volatility can experience steadiness as absence, because the signals they learned to read as love, unpredictability and the sense of being chased, have all gone quiet. The nervous system reports the quiet as something being wrong, and then looks for what. The mind is very good at supplying a candidate.

The flare that arrives with good news is common enough to have generated four competing explanations, and they do not sit comfortably together. Attachment-oriented clinicians treat it as an old model being contradicted by new evidence, uncomfortable precisely because the relationship is working. Behaviorally trained clinicians are more interested in what the person does next, since the flare itself is survivable and the avoidance built around it does the damage. Esther Perel, in Mating in Captivity (2006), argues something less comforting: that security and desire draw on needs which pull against each other, so the settling that calms one can flatten the other. Jungian writers frame the same moment as projection, with the partner receiving material the person has not accepted in themselves; for that framing, see The Shadow Self: What Jung Meant and How to Meet It. The four disagree about cause and agree about timing. The week after something goes right is the worst possible week to make a decision about the relationship.

Why do I want to break up when things are good?

The urge is usually an attempt to control the timing of a loss you have already decided is coming. Ending it now is a smaller, chosen version of being left later, and the immediate relief is easy to mistake for clarity. Wait two weeks before acting on it. Urges that come from an actual decision survive that wait, and urges that come from panic almost never do.

Does relationship anxiety get worse after a partner commits?

Frequently, yes. Commitment removes ambiguity in one direction and raises exposure in the other, so the fear has more to work with rather than less. Engagements, moving in together and pregnancies are common flare points. The flare tends to settle over a few weeks as the new arrangement stops being novel, provided the person does not act on it while it is loudest.

Is a calm relationship supposed to feel boring at first?

It often does, and that is worth expecting rather than diagnosing. If your previous relationships supplied their intensity through uncertainty, a steady partner removes the source of the charge, and the flatness is withdrawal from it rather than a verdict on compatibility. Give it several months and watch whether interest builds on other grounds, such as liking the person's company.

Why does reassurance from your partner stop working so quickly?

Reassurance stops working quickly because the relief it produces is what keeps the doubt in business. Asking do you still love me and hearing yes drops the doubt sharply within seconds, and that drop is a reward. The brain files the sequence as proof that asking is what made the doubt subside, so the next time it surfaces the urge to ask arrives faster and harder. People describe the relief lasting less and less time, an answer that once held for a day holding for an evening, and then for an hour. There is a second reason, and it concerns content. Reassurance answers a question that information cannot settle. Will you leave me is a prediction about the future, and no honest partner can guarantee it, so the answer is always slightly hollow and an anxious listener can hear that. Any hesitation, any word chosen differently from last time, becomes new evidence. A third reason is mechanical: the more often reassurance is requested, the more automatic the answer becomes, and an automatic answer carries almost no information, which is precisely what the questioner was trying to gather.

Anxiety treatment handles this by changing what happens after the urge rather than by arguing with the fear. In practice that means agreeing in advance on what reassurance looks like when it is offered rather than extracted, and gradually letting some requests go unanswered without the relationship collapsing, which is the evidence the fear needs and cannot obtain any other way. Partners usually need this explained to them, because declining to answer feels cruel. It works better framed as a change of kind: I am not going to answer that question again tonight, and I am going to sit here with you. Presence works where content does not, since presence is the thing being doubted in the first place. Couples therapists trained in Emotionally Focused Therapy, developed in the 1980s by Sue Johnson and Les Greenberg, approach the same problem from the other side, working on the loop the pair are running rather than on the sentence either one wants to hear. Both routes take weeks rather than days, and the first fortnight tends to feel worse than the starting point, which is the part nobody warns people about.

How much reassurance is too much in a relationship?

There is no fixed number, so use two other tests instead. Is the relief lasting less and less time, and are you asking a question you already had answered this week? Reassurance that resolves something is fine at almost any frequency. Reassurance that resets a timer is the version that grows, and it exhausts the partner supplying it long before anyone says so.

How do I ask for reassurance without making things worse?

Ask for something a partner can actually do rather than something they have to promise. Can you tell me what you like about us, or can we have Thursday evening with no phones, are requests with real answers. Do you promise you will never leave is not. Naming your own state helps too: say that you are anxious rather than that they are failing, which is the whole difference between a request and an accusation.

What should my partner do when I need reassurance constantly?

Stay warm and stop escalating the content. Repeating a stronger promise each time raises the dose without treating anything. Steady contact, one short honest answer, and an agreement to come back to it later works better, and it should be agreed in a calm moment rather than invented mid-panic. If the demand is consuming their evenings, that is a signal to bring in outside help.

What does relationship anxiety look like early on compared with a long relationship?

Early on, relationship anxiety is mostly about whether the other person is in it, and in a long relationship it is mostly about whether they still are. The content shifts and the machinery does not. In the first months the symptoms attach to gaps in information: reply times, a different sign-off, what silence on a Sunday means, whether the last date was a nine or a seven. Everything is ambiguous because there is genuinely no history to test a prediction against, which is why anxiety in the first months is unremarkable and often means nothing at all. After a year or two the triggers turn domestic. A partner quiet at dinner, a week without physical contact, a friendship you cannot see, a work trip. The fear now has a large body of shared history to mine and can build a case out of it. Long-relationship anxiety is also lonelier, because the early version is socially acceptable and the later version sounds ungrateful. So it goes unmentioned, and an unmentioned fear has nothing working against it.

One useful difference is what the anxiety can be checked against. In a new relationship there is nothing to compare a bad week to, so the fear cannot be falsified, and the only real remedy is time and a few more data points. In a long relationship you hold a baseline, which makes the same fear testable: this is the third quiet stretch this year, the last two ended when a work deadline passed, and this one looks identical. Baselines are the biggest single advantage a long relationship gives an anxious person, and almost nobody uses them, mostly because keeping one requires writing things down during the calm stretches when nothing seems to warrant it. A baseline assembled from memory rather than from notes is close to worthless, because recall runs through the mood you are in while doing the recalling. Ask someone mid-flare how last winter went and they will produce a winter that supports the flare. Clinicians disagree about how hard to push the writing. In the cognitive behavioral tradition the written thought record is a standard tool, since a prediction on paper is a prediction that can turn out wrong in front of you. Emotionally Focused Therapy works from the other end, on the cycle a couple repeats and on what each partner does in the minutes after the other goes quiet, and it leans far less on records kept between sessions. Whether a written log helps a couple or hardens them is not a question either tradition has settled, and the risk of a private record turning into a ledger of grievances is real enough to plan around. The version most people can live with is a private log of your own predictions, never a ledger of your partner.

Is anxiety in a new relationship normal?

Very. The early months contain almost no evidence about how a person behaves over time, so the mind fills the gap with prediction, and prediction under uncertainty feels like fear. Intensity alone is not diagnostic here. What matters is whether it settles as evidence accumulates, or holds steady while everything else grows more secure. The second version is the one to look at.

Why has my relationship anxiety appeared after several years together?

Late onset usually has a trigger, even when it seems to come from nowhere. Common ones include a friend's affair or divorce, a job that changes a partner's hours and social world, a health scare, a new baby, or a stretch where sex or conversation quietly dropped off. Look hard at the last six months before assuming the fear is about the relationship itself.

Does relationship anxiety go away when you get married?

For some people it eases, because the arrangement becomes concrete and the daily uncertainty drops away. For others it intensifies, since the stakes rise and the exit gets harder. Marriage changes the setting rather than the mechanism, which is why people who were seeking reassurance before a wedding are generally still seeking it afterward. Plan for continuity rather than for a cure.

When is relationship anxiety a sign you need help beyond self-management?

Get professional help when the anxiety is costing you function, when it has taken over hours of your day, or when it produces behavior you cannot stop. Concrete thresholds are more useful than a vague sense of coping. Sleep disrupted more nights than not for a month. Work you can no longer concentrate on. Checking or searching that runs for hours. Friendships dropped because you cannot talk about anything else. Physical symptoms on most days. Repeated breakups and reconciliations. Any one of these, on its own, is reason enough to talk to a doctor or a therapist rather than waiting for a worse week to justify it. Two situations skip the queue entirely. If you are having thoughts of harming yourself, contact emergency services or a crisis line in your country now. If your partner monitors you, controls the money, isolates you from people, threatens you, or frightens you physically, the problem is safety rather than anxiety, and a domestic abuse service is the right first call. Both are common enough that nobody should feel unusual making it.

The treatments with the best evidence for anxiety in general are cognitive behavioral therapy and, for some people, medication prescribed by a doctor, and both work on relationship-focused anxiety without needing the relationship to be the subject of every session. Where the doubt behaves compulsively, with rituals and checking and mental reviewing, clinicians often use exposure and response prevention, which national treatment guidelines name as the first-line psychological treatment for obsessive-compulsive disorder. Couples therapy is a different tool for a different problem. It helps when both people are inside the loop and both will attend, and it substitutes poorly for individual work when one person's anxiety predates the relationship by twenty years. Worth saying plainly as well: guided self-help does have a place in formal treatment, and the UK's NICE guideline on generalized anxiety disorder lists low-intensity guided self-help among the options offered before individual therapy. This article is not that. It has not been tested against any of the treatments above, and reading is a reasonable first step and a bad only step.

What kind of therapist should I see for relationship anxiety?

Look for someone trained in cognitive behavioral therapy for anxiety, and describe the specific pattern when you first make contact, including any checking or reassurance-seeking. If the doubt runs in compulsive loops, ask whether they work with obsessive-compulsive presentations. If both of you want to attend together, look separately for a couples therapist rather than expecting one clinician to do both jobs well.

Can medication help with relationship anxiety?

Medication for anxiety is prescribed for the anxiety rather than for the relationship, and whether it suits you is a decision for a doctor who knows your history. Some people find it lowers the baseline enough to make therapy usable. It does not answer the question the doubt keeps asking, and it is generally recommended alongside psychological treatment rather than instead of it.

Should I tell my partner I have relationship anxiety?

In most cases yes, and earlier than feels comfortable. A partner who knows the pattern can respond to it rather than guess at it, and the explanation keeps your withdrawal from being read as lost interest. Say what it is and what helps, without handing them responsibility for managing it. Hold it back only if you have reason to think it would be used against you.

Frequently Asked Questions

Is relationship anxiety normal, or does it mean I am in the wrong relationship?

Relationship anxiety is common and by itself says almost nothing about whether the relationship is right. The distinguishing question is whether the fear is generated by ambiguity or by evidence. Anxiety that runs identically across several partners, calms briefly with reassurance and returns without new information, is about you. Doubt that keeps pointing at specific, repeatable behavior, and that people who know you both quietly share, is worth taking seriously as information about the relationship rather than about your nervous system.

Why do I panic when my partner takes hours to reply?

A delayed reply is the purest form of ambiguity, and an anxious system fills ambiguity with the worst available explanation. Nothing has happened, which means nothing contradicts the story you are building, and every additional minute adds weight to it. The panic is partly physical by then, because the phone itself has become the trigger. Most people find the response drops if they put the phone in another room for a set period rather than watching it, though the first twenty minutes feel worse.

Why is my relationship anxiety worse at night?

Anxiety gets worse at night because distraction ends and nothing competes with the thought. Fatigue lowers your ability to challenge a fear, evening is when reply gaps stretch longest, and lying still with no task leaves the mind free to run scenarios to the end. Alcohol tends to sharpen it a few hours later as it clears. A consistent bedtime, a written note of the worry to deal with in the morning, and keeping the phone out of arm's reach help more than arguing with the thought at two.

Can relationship anxiety go away on its own?

Sometimes. Anxiety in a new relationship often fades within a year as evidence accumulates, and anxiety triggered by one specific event can settle once the event is resolved and enough uninterrupted time has passed. A pattern that has repeated across several relationships rarely clears on its own, because the behaviors maintaining it, checking and testing and reassurance-seeking, keep supplying short-term relief. That version usually needs deliberate change or treatment. Cognitive behavioral therapy has the strongest evidence base of the psychological treatments for anxiety disorders, though how well it works on this particular pattern is not something anyone has measured directly.

How do I stop checking my partner's phone and social media?

Make it harder and slower rather than relying on willpower at the moment the urge arrives. Remove the app from your phone, delay every check by a fixed twenty minutes and write down what you expect to find before you look, and tell one person you are doing this. Checking runs on immediate relief, so friction and delay strip most of its power. Expect the urge to spike before it fades. If the checking is eating hours, that alone is a reason to see a therapist.

Does relationship anxiety mean I do not really love my partner?

No. Doubt about your own feelings is one of the most common forms relationship anxiety takes, and it sets a specific trap: you check whether the love is still there, the checking produces numbness, and the numbness then looks like proof that it has gone. Affection is intermittent and situational in everyone, and it does not survive continuous inspection any more than sleep survives being monitored. Judge it by what you do across months, not by what you feel while examining it.

Is it normal to feel this anxious in a new relationship after being cheated on?

Yes, and the vigilance is a learned response to something that actually happened rather than an overreaction. Betrayal teaches the nervous system that ordinary signals can hide a serious threat, so a new partner's late night sets off a response calibrated to the last relationship. The alarm is accurate about the past and wrong about the present. For many people it eases over months as new evidence accumulates, and faster if the new partner is transparent without being asked. If it is not easing at all, trauma-focused therapy is the right place to take it.