Extramarital Affairs: Why They Happen and What the Research Actually Says

You are not here because everything is fine.

You are here because something shifted, and you cannot name it yet. Maybe it is the way your partner holds their phone now. Maybe it is a stomach-drop moment that happened weeks ago and you have been trying to explain away ever since. Maybe you have been staring at the ceiling at 2am running the same loop and you finally typed the thing you have been afraid to search.

Whatever brought you here, you deserve a straight answer.

The General Social Survey found that 20% of men and 13% of women admit to sex outside marriage. When emotional affairs are included, the AAMFT estimates those numbers climb to roughly 45% of men and 35% of women. Extramarital affairs are not rare. They are not something that only happens to other people's marriages. And they are not always obvious, even to the people living inside them.

This article is not here to catastrophize your situation. It is here to give you the information you actually need: what an affair is, why they happen, what the signs look like before people want to see them, and what the research says about what comes next.

What Makes an Affair an Affair

The legal definition is simple. The emotional reality is not.

Most people think of an extramarital affair as a purely physical event. A hotel room. A secret. But that framing misses the most common version of what actually happens.

Dr. Shirley Glass, one of the leading researchers on infidelity, identified that 82% of affairs begin with someone the person already knows, usually described as "just a friend." The affair does not start with a decision to cheat. It starts with a friendship that slowly crosses invisible lines, where more and more emotional intimacy gets shared outside the marriage, and less and less gets brought home.

That is what researchers now call an emotional affair. And for many people, it is where the real damage begins.

An emotional affair involves:

• Secrecy around the relationship, even when nothing physical has happened
• A level of emotional intimacy that exceeds what is shared with your partner
• Comparing your partner unfavorably to the other person
• Energy and attention being redirected away from the marriage

Dr. Sue Johnson, the founder of Emotionally Focused Therapy, describes affairs as often being about attachment needs. Not lust. Not boredom in the simple sense. People seek out emotional connection when they feel unseen or unreachable in their primary relationship. The affair becomes the place where they feel understood, desired, and present in a way that has stopped happening at home.

That does not make it less of a betrayal. It makes it more complicated to understand and more painful when you realize it.

You can read more about how emotional betrayal works in our piece on emotional cheating, which walks through the specific behaviors and patterns that define it.

Why Affairs Actually Start (Not What People Think)

The narrative most people carry is about temptation or weakness or bad people making selfish choices. The research tells a different story.

A 2023 PMC/NIH paper, "Love and Infidelity: Causes and Consequences," found that people who cheat are rarely doing so because their marriage is simply bad. The causes are layered. They include unmet emotional needs, individual psychological factors, opportunity, and what researchers call "self-expansion," the human drive to feel like you are growing and becoming more.

Gottman Institute research, drawing from what they call the Gottman-Rusbult-Glass Cascade, documents the slow path toward betrayal. It typically looks like this:

Emotional distance develops in the marriage. Small conflicts go unresolved. Partners start turning away from each other instead of toward each other. Then an opportunity appears, usually in the form of someone who is present, interested, and available in the ways the marriage has stopped being.

A 2024 study found that 31% of affairs involve a coworker. That is not coincidence. Workplaces create exactly the conditions the research describes: shared stress, proximity, a sense of being understood in a context your partner is not part of, and hours of daily contact that build familiarity faster than most people realize.

Warach et al. (2024), a meta-analysis published in the journal Personal Relationships, identified that individual factors including attachment anxiety, sexual dissatisfaction, and a tendency toward thrill-seeking, combined with relationship factors like low commitment and unresolved conflict, predicted infidelity more reliably than any single cause alone.

What this means for you is that if your partner had an affair, or you suspect they might be moving toward one, it is almost never as simple as "they found someone more attractive." That is the story people tell because it is easier than the truth, which is about emotional architecture and what was being built or allowed to erode over time.

The 7 stages of emotional affairs breaks this progression down in detail if you want to understand how the trajectory typically unfolds.

The Signs That Were There Before You Wanted to See Them

This is the part that is hardest to read.

Because most people, when they look back, realize they knew something before they were ready to know it. The gut feeling that something was off. The moment when you looked at your partner's face and could not quite find them there.

Here are the behavioral patterns researchers and clinicians identify most consistently:

Changes in phone behavior. The screen that was always face-up is now face-down. The phone that used to charge on the nightstand now charges in another room. Texts that prompt a quick exit from the room.

Emotional withdrawal. Not necessarily anger or coldness, but absence. The sense that your partner is physically present but not actually there. Conversations that stay surface-level. Intimacy that feels obligatory rather than real.

New defensiveness. Asking simple questions and getting responses that feel disproportionate. Being accused of checking up when you are having a normal conversation.

Unexplained schedule shifts. Work that suddenly requires more nights. A new workout routine that was not there before. Time that is accounted for loosely or inconsistently.

Interest in appearance that feels new. Not maintenance, but a sudden attention to how they look before certain situations.

Pulling away from your shared social world. Less interest in mutual friends, family events, or the routines that used to be shared.

No single item on this list means anything conclusive on its own. But a cluster of these patterns, especially when they appear together after a period of emotional distance, is information worth paying attention to.

If you are trying to make sense of what you are noticing, the relationship risk assessment is designed to help you organize those observations into a clearer picture.

What the Research Says About Staying or Going

People search for a clean answer here and there is not one.

What the research does offer is this: recovery from an extramarital affair is possible, but it requires specific conditions and it is rarely fast.

The Gottman Institute's research on couples who survived infidelity found that the critical variable was not whether the affair happened, but whether both partners could engage honestly with what it meant and what in the relationship created the conditions for it.

Dr. Sue Johnson's Emotionally Focused Therapy has one of the strongest evidence bases in couples therapy. EFT focuses specifically on the attachment injuries that affairs create and the process of rebuilding emotional safety. Studies on EFT show meaningful recovery rates, but the process typically takes longer than people expect and requires both partners to be genuinely engaged.

Affairs that are minimized, where the person who cheated insists it meant nothing and pushes for quick forgiveness, tend not to resolve. The wound goes underground. It resurfaces.

Recovery, when it happens, usually involves:

• Full disclosure, over time, not all at once
• Genuine accountability without defensiveness
• Understanding what conditions in the relationship and in the individual contributed to the affair
• Rebuilding trust through consistent behavior, not promises
• Professional support, specifically with a therapist trained in infidelity recovery

If you are trying to assess where your relationship actually stands before making any decisions, the couples therapy for trust issues article walks through what that process looks like and what to expect.

And if you are not yet sure whether what is happening in your relationship crosses the line into something serious, the relationship risk assessment gives you a structured way to evaluate what you are experiencing.

What to Do Right Now

You do not have to make any decisions today.

But you do have to stop pretending that what you are feeling is nothing, because you would not be here if it were nothing.

The most useful thing you can do right now is get clear. Not clear about what you are going to do, but clear about what is actually happening. That means paying attention to the patterns. It means trusting the data your nervous system has been collecting, not as proof, but as information worth taking seriously.

If you have a partner who seems to be drifting, or who has already crossed a line you cannot undo, the research is consistent on one thing. The longer the avoidance, the harder the recovery. The conversations you are afraid to have are the ones that need to happen.

If you want to understand your relationship's risk profile before you do anything else, start with the quiz. It takes about two minutes and it is built on the behavioral and psychological research this article draws from.

You came here because something told you to look. That is not weakness. That is intelligence.

Frequently Asked Questions

How common are extramarital affairs?

More common than people admit publicly. The General Social Survey found that 20% of men and 13% of women report having sex outside marriage. When emotional affairs are included, the AAMFT estimates those numbers climb to roughly 45% of men and 35% of women. The actual numbers are likely higher, since self-reporting on infidelity is notoriously unreliable.

Are women cheating more than they used to?

Yes. Women's infidelity has increased approximately 40% over the last 20 years. Among adults aged 18 to 29, women now report cheating at a slightly higher rate than men, 11% versus 10%. This is a significant shift from historical patterns and challenges a lot of assumptions people still carry.

Can a marriage survive an extramarital affair?

Research says many do, but survival requires specific conditions. Couples who pursue structured therapy, particularly Emotionally Focused Therapy, show meaningful rates of recovery. Gottman Institute research indicates that recovery is possible when both partners are willing to do the difficult work, but it is not guaranteed, and it is never quick.

What is the difference between an emotional affair and a physical affair?

An emotional affair involves a deep, intimate bond with someone outside the marriage, including secrecy, emotional dependency, and energy that is redirected away from your partner, without physical contact. Many therapists argue emotional affairs are equally or more damaging because they involve a level of psychological intimacy that threatens the primary relationship's foundation.

Where do most affairs start?

The most common starting point is friendship. Dr. Shirley Glass found that 82% of affairs begin with someone the person already knows, often described as "just a friend." A 2024 study found that 31% of affairs involve a coworker specifically, which makes sense given the amount of time, proximity, and shared stress that workplaces create.

How do I know if my partner is having an affair?

There is no single definitive sign, but patterns matter. Behavioral shifts, changes in digital habits, emotional withdrawal, and shifts in social patterns, taken together, tell a clearer story than any one thing in isolation. If something feels wrong, that feeling deserves to be taken seriously. Taking a structured assessment can help you organize what you are noticing.