No, cheating once does not mean a person will always cheat, but it does raise the risk. In a 2017 study in *Archives of Sexual Behavior*, 45% of people who had cheated in one relationship reported cheating in their next one, compared with 18% of everyone else. So most past cheaters did not do it again. At Love Answers, we read the studies behind the advice and say how strong the evidence is, and this one is useful but narrow.
The odds matter less for your decision than the behavior in front of you. Whether the person who cheated tells the whole truth, ends contact and answers your questions without anger says more about the next year than any average.
Once a Cheater, Always a Cheater Is a Myth With a Grain of Truth
Past cheating is linked to a higher chance of cheating again, but it does not decide the future. The clearest data comes from a 2017 study by Knopp and colleagues in Archives of Sexual Behavior. They followed 484 unmarried U.S. adults aged 18 to 35 through two romantic relationships and asked about sex outside each one.
| Group in the study | What they reported in the next relationship |
|---|---|
| Cheated in the first relationship | 45% reported cheating again |
| Did not cheat in the first relationship | 18% reported cheating |
| Knew a past partner had cheated | About 2 times the odds of reporting the next partner cheated |
| Only suspected a past partner | About 4 times the odds of suspecting the next partner |
People who cheated in the first relationship had about three times the odds of doing so in the next one. Odds are a statistical measure and differ from a plain probability, so “three times the odds” does not mean “three times as likely”. The plainer reading is the first row: fewer than half of past cheaters reported doing it again.
What the Study Cannot Tell You
The study has limits that matter for your decision. Everyone in it was unmarried and young, so it says little about a 20-year marriage. It measured sex outside the relationship, so emotional affairs and micro-cheating were not counted. It also relied on people reporting their own behavior, and some people underreport.
Why One Affair Does Not Predict the Next
The reason someone cheated shapes whether it is likely to happen again. A study by Selterman and colleagues in the Journal of Sex Research, described by the University of Maryland, asked nearly 500 people who had cheated why they did it. It found eight motives:
- Anger at a partner
- Sexual desire
- Lack of love
- Feeling neglected
- Low commitment
- The situation, such as drinking, travel or stress
- Self-esteem
- A wish for variety
Researchers also found a tendency for affairs driven by anger or lack of love to last longer and end the main relationship more often, while situational affairs were shorter, according to PsyPost’s coverage of the study. The participants averaged about 20 years old, so treat this as a lead to explore. Our guide on why people cheat goes through each motive.
A one-night mistake on a work trip that the person disclosed and regrets is a different problem from an affair that grew out of years of feeling unloved. The second one will not stop being a risk until the couple deals with the distance that came before it.
Signs a Cheater Has Changed
You can tell more from behavior over several months than from any promise made in the first week. The table sets the behaviors we would watch next to the ones that point toward a repeat.
| Signs of real change | Signs of repeat risk |
|---|---|
| Tells the whole story early, without being caught piece by piece | Admits only what you already found, then more comes out later |
| Ends all contact with the affair partner and tells you if the person reaches out | Keeps a “friendship” with the affair partner or hides contact |
| Answers your questions, even the third time you ask | Gets angry or says “I already told you” when you ask |
| Names their own part without blaming you | Says the affair happened because of something you did |
| Offers openness, like showing the phone or sharing location | Treats any request for openness as an insult |
| Starts individual therapy or couples therapy and keeps going | Agrees to therapy, then cancels sessions |
The first column matches the first phase of the Gottman Institute’s affair-recovery model, which it calls Atone. In that model the person who cheated takes responsibility and answers questions before the couple moves to Attune and then Attach. Gottman’s three phases are a clinical model, and the Gottman Institute gives no success rate for it.
Disclosure seems to matter too. In a small 2005 study of 134 couples in behavioral couple therapy, the 19 couples dealing with infidelity started out more distressed. The researchers found that those whose affair was disclosed before or during therapy improved faster than the other couples. With only 19 couples, read it as a hint.
If You Are the One Who Cheated
You lower your own risk of a repeat by understanding what led to the first affair and changing those conditions. Ask yourself which of the eight motives above fits, and be specific. “I was bored” usually hides something more useful, like “I stopped telling my partner when I felt lonely.”
Then make the changes visible to your partner. End contact in writing, stay out of the settings where it started for a while, and answer questions without keeping score. Individual therapy helps here, because a therapist can work on your part without your partner in the room.
What the Odds Mean If You Are Deciding Whether to Stay
The research supports giving a first affair a real chance at repair when the person who cheated does the work in the left column of the table. It does not support staying through repeated affairs, repeated lying or a partner who refuses to answer questions. Our should I stay quiz weighs those factors with you, and our guide on affair recovery sets out what the months after disclosure tend to look like.
If you choose to try, the rebuilding a relationship after cheating guide gives a phased plan, and the rebuilding trust guide covers the daily habits. Our free rebuilding trust worksheet gives you both a place to write down agreements.
When Our Answer Does Not Apply
Our “usually not” answer does not fit every case. It does not fit if your partner has cheated more than once after promising to stop, or if the cheating comes with threats, control or fear. Couples counseling is usually not recommended while abuse is happening. Reach the National Domestic Violence Hotline at 1-800-799-7233 or text START to 88788, and see our guide to a toxic relationship.
What Would Change Our Answer
A large study of married couples showing that most people who cheated did so again would change our answer. So would a second affair after disclosure and recommitment, because the person has now shown how they act after being caught. If either happens, protect yourself first and read how to get over being cheated on.
This week, pick two behaviors from the left column of the table and ask your partner for both, then watch for a month before you decide whether once a cheater, always a cheater holds true for them.