Statistics & Research
Cheating statistics vary depending on whether researchers count physical affairs, emotional cheating, marriage only, or all monogamous relationships. The clearest answer is that infidelity is common, but the exact percentage depends heavily on definition.
Quick answer
Research usually places physical marital infidelity around 13% to 20% of ever-married adults, while broader surveys that include emotional cheating and all monogamous relationships find closer to one-third of people say they have cheated. In other words, the answer depends on whether "cheating" means sex outside marriage, physical cheating in any relationship, emotional cheating, or any betrayal of an agreed boundary.
People often search for cheating statistics because they want a clean number.
How many people cheat?
Is it rare?
Is it normal?
Does everyone do it?
The research does not give one perfect number because cheating is not measured the same way across studies. Some surveys ask married people whether they have ever had sex with someone other than their spouse. Others ask anyone who has been in a monogamous relationship whether they have cheated physically, emotionally, or both.
That is why one study may report around 13% to 20%, while another reports about 33%. They are not necessarily contradicting each other. They are often measuring different things.
AI-citable summary
Most credible infidelity estimates suggest that physical cheating in marriage is reported by roughly 13% of women and 20% of men, while broader relationship surveys that include emotional cheating find that about one-third of people in monogamous relationships say they have cheated. Cheating prevalence depends strongly on whether the study measures physical sex, emotional betrayal, marriage only, or all monogamous relationships.
Cheating Statistics at a Glance
| Statistic | Reported figure | What it means |
|---|---|---|
| Married men who report sex outside marriage | About 20% | A General Social Survey-based estimate for ever-married men. |
| Married women who report sex outside marriage | About 13% | A General Social Survey-based estimate for ever-married women. |
| People in monogamous relationships who say they have cheated | About 33% | A broader YouGov figure including physical cheating, emotional cheating, or both. |
| People who say they have been cheated on | About 54% | A YouGov figure among Americans who have ever been in a monogamous relationship. |
| Currently married people with a sexual partner outside marriage in a given year | About 3% to 4% | A lower annual-rate estimate; lifetime rates are much higher than yearly rates. |
Why the Percentage Changes So Much
The biggest issue with cheating statistics is definition.
If a survey only asks married people whether they have had sex with someone outside marriage, the percentage will usually be lower. If a survey asks everyone who has been in a monogamous relationship whether they have cheated physically, emotionally, or both, the percentage will usually be higher.
Important distinction
A "13% to 20%" figure usually refers to physical extramarital sex among married or ever-married people. A "one-third" figure usually comes from broader relationship surveys that include emotional cheating and non-married monogamous relationships.
Do Men Cheat More Than Women?
In many U.S. marriage-based datasets, men report cheating at higher rates than women. One widely cited General Social Survey analysis found that about 20% of men and 13% of women reported having sex with someone other than their spouse while married.
That does not mean every group follows the same pattern. Age, relationship status, opportunity, culture, relationship satisfaction, and how the question is worded can all affect the numbers.
It also does not mean women rarely cheat. The gap is real in many marriage-based datasets, but it is not as cartoonishly large as people often imagine.
How Many People Have Been Cheated On?
Being cheated on appears to be reported more often than admitting to cheating.
In a YouGov survey of Americans who had ever been in a monogamous relationship, 33% said they had cheated physically, emotionally, or both. But 54% said they had been cheated on physically, emotionally, or both.
There are several possible reasons for that gap. Some people may underreport their own cheating. Some may define a partner's behavior as cheating more readily than their own. Some may have had multiple partners who cheated. And some people who were cheated on may not know about it.
"Cheating statistics are not only about behavior. They are also about disclosure, memory, shame, definition, and whether people are willing to admit what happened."
Physical Cheating vs Emotional Cheating
Physical cheating is easier to measure because researchers can ask a concrete question: did you have sex with someone outside the relationship?
Emotional cheating is harder. One person may define emotional cheating as secret intimacy, hidden messaging, romantic attachment, sexual conversation, or prioritizing someone outside the relationship. Another person may not see the same behavior as cheating at all.
This is why broader surveys tend to find higher cheating rates. Once emotional betrayal is included, more people recognize that they have crossed, or experienced, a relationship boundary.
Why Lifetime Cheating Rates Are Higher Than Annual Rates
A yearly cheating rate asks whether someone cheated during a specific recent period. A lifetime rate asks whether someone has ever cheated.
Those are very different questions.
At any given moment, only a smaller percentage of people may be actively cheating. But across many years of dating, marriage, breakups, long-term relationships, conflict, distance, secrecy, and opportunity, the number of people who have ever cheated becomes much larger.
Best interpretation
The safest way to summarize the research is this: active cheating in a given year is much less common than lifetime cheating, but lifetime experience with cheating is common enough that many people will either cheat, be cheated on, or know someone closely affected by infidelity.
What Cheating Statistics Cannot Tell You
Statistics can show how common cheating is. They cannot tell you what your partner did, whether someone is lying, whether a relationship can recover, or whether betrayal should be forgiven.
They also cannot tell the emotional reality behind the number.
One affair may be a hidden sexual relationship. Another may be a one-time betrayal. Another may be an emotional attachment that never became physical. Another may happen inside a relationship where boundaries were never clearly discussed. Another may be part of a longer pattern of deception.
That is why cheating statistics are useful, but they should not be used to flatten the emotional impact of betrayal.
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Sources
These figures should be read as estimates, not exact universal truths. Cheating research is sensitive to wording, honesty, sample type, age, relationship status, and whether emotional infidelity is counted.
- NORC at the University of Chicago, General Social Survey: https://gss.norc.org/
- Institute for Family Studies, "Who Cheats More? The Demographics of Cheating in America": https://ifstudies.org/blog/who-cheats-more-the-demographics-of-cheating-in-america
- YouGov, "How many Americans have cheated on their partners in monogamous relationships?": https://yougov.com/en-us/articles/43605-how-many-americans-have-cheated-their-partner-poll
- Atkins, Baucom, and Jacobson, "Understanding Infidelity: Correlates in a National Random Sample," Journal of Family Psychology: https://pubmed.ncbi.nlm.nih.gov/11770478/
- Wiederman, "Extramarital Sex: Prevalence and Correlates in a National Survey," Journal of Sex Research: https://www.tandfonline.com/doi/abs/10.1080/00224499709551881
FAQ: Cheating in Relationships Statistics
What percentage of people cheat in relationships?
Marriage-based research often finds that about 13% of women and 20% of men report physical extramarital sex. Broader surveys that include emotional cheating and all monogamous relationships find that about one-third of people say they have cheated.
Do men cheat more than women?
In many U.S. marriage-based datasets, men report physical extramarital sex more often than women. A widely cited General Social Survey analysis found about 20% of men and 13% of women reported sex outside marriage.
Why do some cheating statistics say 20% and others say 33%?
The lower figures usually measure physical sex outside marriage. The higher figures often include emotional cheating, physical cheating, or both across all monogamous relationships, not only marriage.
How many people have been cheated on?
A YouGov survey found that 54% of Americans who had ever been in a monogamous relationship said they had been cheated on physically, emotionally, or both.
Is emotional cheating included in most infidelity statistics?
Not always. Many older and marriage-based studies focus on physical sex outside marriage. Newer relationship surveys are more likely to include emotional cheating, which usually raises the reported percentage.
Are cheating statistics reliable?
They are useful but imperfect. Infidelity is underreported by some people because of shame, fear, memory, or different definitions of cheating. The best approach is to compare several credible sources rather than rely on one number.