Once a cheater, always a cheater? Well, not always but the risk does rise, according to some recent research.

Prior infidelity can triple the chance of cheating on a current partner. But it turns out that whether you’ve had a partner who’s had an affair is also a factor. It normalizes infidelity, turns out. If it happened to you, it must be common, the thinking goes.

Historically, the research found that men consistently engaged in more affairs than women. Not according to research. Here cohabitating women are just as likely to step out. They were 3.4 times more likely to cheat long-term.

The survey of 484 cohabiting adults asked about their relationship history extending back five years. Participants were asked if they were having sex with someone else in their current or if they had in their previous relationship. It also asked about their knowledge of their partners.

Almost 45% of the study subjects reported cheating in their previous relationship. 44% in their current relationship. In addition, almost one-third said they knew their spouse had been unfaithful in the past.

The most well-established demographic finding is that men are more likely to commit infidelity than women. It wasn’t the case in this research finding. Perhaps monogamy is less true of women prior to marriage.

Is Once a Cheater Always a Cheater true?

Your partner cheated, and the healing process took an extended period of time. It takes a while to recover from infidelity, but slowly they regained your trust. Perhaps you now see a red flag that reminds you of that earlier period prior to healing. Should you trust your previously unfaithful partner?

Two important factors for serial cheaters are:

1) the availability and quality of other partners and,

2) people’s views on whether cheating is okay.

First, having an affair means that you know the alternative not only exists but remains available to you. Second, individuals who have been unfaithful are likely to have more approving or permissive attitudes.

Increased suspicions

Having a lover that is unfaithful has lasting scars, even into the next relationship. Those who had been cheated on in the past were four times more likely to suspect their current partner. However, their own fidelity (or lack of it) didn’t impact how suspicious they were of their current partner. The key was whether they were the hurt partner in a previous relationship.

Dr. Knopp found that individuals who have committed infidelity themselves, known about their partner’s infidelity or suspected a partner of infidelity are more likely to repeat infidelity in their subsequent romantic relationships.

Trust and commitment

Cohabitating couples are at greater risk for infidelity. This research was based on a non-married cohort, and married couples act differently than non-married ones. Among this research, 44% of the participants were involved with others or had been. This figure is significantly lower for studies limited to married couples.

Will history repeat itself?

Infidelity can be a significant breach of trust and have a lasting impact on a relationship. However, it doesn’t mean that a person is destined to repeat the behavior. People’s behaviors and actions can and do change over time.

Whether or not they will cheat again depends on various factors, including their personal growth, commitment to self-reflection, willingness to address the underlying issues that led to the infidelity, and their ability to rebuild trust within the relationship.

Someone who has been unfaithful in the past can learn from their mistakes, grow, and develop a more faithful and trustworthy approach to relationships.

It is important to talk to your partner about their attitudes toward affairs, personally as well as in general. Is it acceptable for their friends or family to be unfaithful? What harm does it do? Overall attitudes about infidelity seems to have some correlation with the likelihood of it happening again.

This research didn’t investigate open relationships or emotional affairs.


The study was published in the journal Archives of Sexual Behavior (Knopp et al., 2017).

Originally published August 6, 2018