Why Do People Cheat? 1 Psychologist Explains

7 Dec ‘22
7 min
Annemarie Andre
Reviewed by psychologist Pia Linden
From a passionate kiss with a flatmate to an affair that ended in an engagement: three women tell us about the reasons why they cheated on their partners. Psychologist Pia Linden explains why we humans have affairs in the first place and what honest communication with all parties involved would look like.


This article – along with the current divorce rate – is not for hopeless romantics. In the UK, 42% of marriages end in divorce. “Until death do us part” actually looks like four to eight years for many people. Even outside of marriage, relationships break down for a variety of reasons – one of these is infidelity. But why exactly do people cheat?


“I was excited and turned on by the kiss, but it made me feel guilty.”


Marian* had been with her partner for three years when she cheated. There wasn’t a trigger for it, everything happened very slowly. My partner was really stressed out at work and since I often worked from home with my best friend, I began to share more of my life with him than I did with my partner,” explained Marian. Gradually she started to feel that she was emotionally closer to her best friend than she was to her partner.


One evening, when it came time to leave, something happened. We drunkenly admitted we really liked each other and confirmed our feelings with a passionate kiss.” Afterwards, she was overcome with guilt. On the one hand, Marian had been excited by the kiss, but on the other hand, it raised the question of how she was going to resolve this issue and continue her relationship.


I told my partner about it straight away the next day, which was really hard. I just couldn’t lie and say that the kiss meant nothing,” says Marian. As a result, Marian’s partner broke up with her. “He felt that I wasn’t really sure about him and he couldn’t be with somebody who had feelings for somebody else.”

Two roommates, one happy, one sad

“He saw me as I’d always wanted to see myself, but never did”


Klara thinks looking back that she should have walked away from her two-and-half-year relationship sooner. She couldn’t bring herself to do it – until suddenly this new person came into her life. “He triggered some attachment needs from my childhood and gave me what I was missing in my relationship,” she explains.


She quickly separated from her partner to figure out what she actually wanted – independently of the affair. However, she didn’t tell her partner about the new person because she didn’t want to cause him any more pain. I was caught between ecstasy and incredible rushes of adrenaline because I’d just turned my whole life on its head – it was falling in love and major life changes all at the same time.”


Klara is now engaged to the person she was having an affair with. Despite this, she doesn’t have a rosy view of everything that happened. The affair caused a lot of pain, even after I separated from my partner. The person I was having an affair with was torn between two women and initially decided in favour of the other woman before we both realised that we couldn’t live without each other,” she explains.

Woman holding engagement ring up.

“I was happy about the emotional connection that came from cheating”


At the time she cheated, Anna had been feeling for a long time that her partner was emotionally absent. “When I met up with a good friend whom I felt comfortable with, it was natural that we’d hook up,” she explains.


Afterwards, she was torn: on the one hand, she felt terrible, but on the other hand, she was also happy about the emotional connection that came from it.


Anna didn’t say anything at first. It wasn’t until two years later that she shared with her partner what had happened. It came out at an emotional moment when I was feeling safe,” Anna explains and continues: I was under the impression that he was going to let it go because some time had passed, but he wasn’t being honest, so in the end, it wasn’t resolved.” Ultimately, Anna and her partner separated.

Woman sitting on a chair thinking about a guy.

Why do people cheat (psychologically speaking)?


There are certainly plenty of reports about happy people who cheat. However, in many relationships, as the experiences of Klara, Anna and Marian show, there’s a bigger problem. Some factors make cheating more likely. 


“Infidelity tends to happen when there’s distance or disagreements between partners,” explains psychologist Pia Linden. “That might be because someone feels lonely, misunderstood or that their expectations aren’t being met in the relationship.”


For Pia, a healthy relationship is often connected to mutual expectations. “It’s always a good idea to examine your own expectations for the relationship and to review these together regularly. This way, you can both constructively work on any unfulfilled needs or decide together that the relationship isn’t meeting your respective expectations.” 


In addition, you can start working on a relationship in the early stages. “Talking is everything. When you express your expectations, you can respond to them as a couple. If, for example, you’re craving more excitement, then you can figure out together what that might look like,” says Pia.


💡Also interesting to read: A Psychologist’s Guide to Having Better Relationships

When sparks fly, it means the chemistry is right

Every relationship – even an affair – exists as the result of the right (bio)chemistry. What happens in our bodies when we find someone attractive?


Being in love involves a potent cocktail of hormones. Adrenalin, oxytocin, vasopressin, testosterone, dopamine and serotonin are the most significant hormones and neurotransmitters that flood our bodies in these moments. Oxytocin is often known as the “cuddle hormone”. Our brain releases it when we feel a strong or intimate bond. Oxytocin makes us feel less stressed, more confident and more trusting of other people.


Research suggests that some people are born more faithful than others. The reason for this is a so-called fidelity gene. The brain’s reward system has receptors for the hormone vasopressin. The higher the receptor density, the more faithful the partner – at least according to a study carried out on voles. 

It happened! What now?


Should I confess or not? This is a question faced by many people who have cheated, or maybe even had a prolonged affair. “There’s no easy way to tell someone you cheated. It’s important to consider what you want to achieve with this conversation,” explains Pia Linden.


First, it’s important to clarify for yourself what this act of infidelity meant. “Think about how these events came about, what contributed to them? What were your reasons? What expectations related to relationships were behind this behaviour?”


Here, it’s particularly important to express what you did and the feelings involved. “Make sure that you’re expressing yourself clearly and not using vague phrasing or leaving things up to interpretation. For example, say: “I had sex with X on three separate occasions”, instead of “I had sex with someone else a couple of times”. Don’t try to play down this difficult situation by lying. Be prepared to go into the (dirty) details.”


It’s not the right time to defend your actions. “Make sure you’re being honest – to yourself too – about what led to the infidelity,” says Pia. 


Important: Even if you’ve done something that’s considered unacceptable in your relationship, you aren’t now the scapegoat for everything. Psychologist Pia Linden puts it this way: “Cheating doesn’t give anyone the right to assault you or abuse the situation. You don’t have to give up your right to privacy or allow someone to control your life just because you cheated.”


📚 Something that might be of interest: How to Have a Difficult Conversation with Somebody


How OpenUp can support you


A couple’s therapist is the best person to help you actively work on your relationship. They will also give you the opportunity to work on your mutual expectations. Having a conversation with an OpenUp psychologist can play an important role if you’re thinking about confessing to an act of infidelity or if you want to figure out what you really want from your relationship.


* Names have been changed to maintain confidentiality

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