The Science of Why People Cheat: Scientists Reveal the Two Main Reasons Behind the Popularity of Ashley Madison


The popularity of cheating site Ashley Madison shocked the world last month. The reasons why people join such sites  and cheat may be varied, but according to researchers, they boil down to two main causes; boredom and emotional support.

The first reason is largely acted on by people who are not happy with their sex lives, according to relationship expert, Professor Pepper Schwartz.  ‘They’ve been in a relationship for a long time, and they long for the excitement of something new,’ the University of Washington professor told Live Science.  ‘Oftentimes, these people aren’t actively looking for an affair, but they take advantage of meeting a cute crush at a conference, workplace or reunion.’

According to Eric Anderson, chief science officer at, this is reflected on the site.  Most women who joined it said they weren’t unhappy with their partner, and didn’t want a divorce, they just wanted excitement.  The same can’t be said for the second category of people who are unhappy in their relationships. ‘They don’t want to leave for various reasons – children, money, you name it — but they’re just sort of aching for something that’s emotionally reinforcing,’ Schwartz said.  ‘The vast majority of cheaters aren’t willful philanderers, but instead wind up getting involved almost by accident rather than by design,’ relationship expert Dr Duana Welch told

‘Science shows that the progression goes like this: They meet at work, where they’re thrown together again and again.  ‘First, they tell themselves and each other that they’re attracted, but that they’d never act on it, because they’re happily married”.  ‘Their second mistake is building emotional walls in their marriage, and windows with their co-worker.  ‘Third, they start spending time together away from the office, whether on lunches, dinners, or business trips. This is usually when they physical side of the affair begins.’ Catch a Cheater Holding Hands

Dr Welch, who is the author of Love Factually, says that surprisingly, lots of research indicates that men who cheat do it whether or not they’re happy with their marriage.  ‘One study even indicated that the men who were doing the most cheating were the happiest in their marriages, although there’s no way to know whether that’s cause-effect,’ she said.  ‘But one thing that’s clear is that being happy in the primary relationship does not protect the relationship from the male partner’s potential for affairs.’

Happiness plays more of a role with women, who are in fact a lot likelier to cheat if they feel lonely in their marriage or partnership.

Men and women also have different patterns to their affairs; men tend to be most likely to cheat if they are highly successful and so are more attractive to women, travel a lot for work and so have low accountability, or simply believe they are entitled to get some on the side.

Women tend to cheat more if they have a shot at a man with superior genes, while their mate pays the bills. 


  • It has often been the case that cheating partners who get caught have a long list of excuses to explain away their liaisons.
  • But now scientists have discovered an ‘infidelity gene’ that could mean cheating women will be able to simply say their genes made them do it.
  • Females who carry a specific variant of a gene which affects social behaviour and sexual motivation have a greater propensity to take part in ‘extra pair mating’, researchers from the University of Queensland in Australia found.
  • Variants of combinations of the AVPR1A gene have been found to be associated with promiscuity and ruthlessness in animals, the Sunday Times reported.
  • Each person carries two AVPR1A genes – one inherited from each parent – so there are a number of potential combinations.
  • But these variations only appear to affect females rather than males.
  • Dr Brendan Zietsch, a professor of psychology at the university, worked with a team of geneticists and neuroscientists to examine the DNA and lifestyles of more than 7,000 people.
  • They found that of the 6.4 per cent of women who had been unfaithful, a large amount of them had a specific variant of the ‘infidelity gene.’

As for whether you should tell your partner about your affair, therapists and scientists disagree; almost all therapists say no.  However, the best scientific studies indicate that if you don’t tell, there’s a layer of shame and mistrust and a wall that will keep you and your marriage from being truly intimate. ‘More than that, couples who tell their partners have a higher rate of full recovery – including saying they are closer, and better, than before,’ said Welch.


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