There are several different reasons that people find themselves driven to cheat on their partners.
Some are complex and could be because the guilty party has met someone else, or it could be driven by self-destruction. Or it could be a simple as falling out of love.
But is there ever a good enough justification for infidelity?
Now someone has taken to Reddit to try and find out what made cheating spouses betray their other half.
The user, known only as RaxsonCZ, asked: "People who cheated on their SO (significant other), what was your logic?"
In just two weeks, there have been over 1,600 comments and people have been honest about why they strayed and what happened afterwards.
Sometimes, it seems there was no logic at all.
With the words "once a cheat, always a cheat" constantly attached to those who stray, decide for yourselves what you would do in their situation.
One Redditor told the forum they cheated during their 16-year marriage because her husband would make excuses not to have sex every night - and then masturbate instead.
After one confrontation, he told her to go and find a boyfriend but warned that no one else would want her.
She says: "So, I did. Should I have cheated? No. But one partner does not get to totally dictate the couples sex life."
Another person was more matter-of-fact. Curlaub wrote: "No logic. Just hormones and regret."
Loganbad101 broke it down even more simply by saying: "I.Was.Horny."
One person's infidelity even caused the break-up of a family.
Asdf1996 said they had been cheated on multiple times and was comforted by their partner's cousin when things "just happened."
They wrote: "I am not proud of it, I broke up a family and turns out his cousin was a stalker."
Refrith explained that he was in a serious car accident and that his girlfriend was busy and couldn't be there for him in the way that he wanted. Instead, his ex was.
Another Redditor revealed that they were in an emotional and later physical affair, adding: "Someone finally took an interest in me and made me feel beautiful, so I slept with him."
Gilga-Mosh took to Reddit to admit that the reason he cheated was because he and his wife both had very poor communication and were insecure.
Another said their significant other two-timed them multiple times and so one day they got drunk and cheated too.
The next day, they left their partner and it was the best decision they ever made.
Ktreaty said she was in a bad way due to mental health and was feeling self-destructive. The truth is, she says: "'I wasn't thinking about my SO at all when I did those things, even though I loved them deeply.
"I just wanted to kill myself without killing myself."
Boblogbob took to the forum and admitted to sleeping with his ex, saying: "I could have done a lot of things differently and I'm filled with regret but that ruined the beginning of the best relationship I've ever had. It destroyed trust and its all my fault...Lying is a death sentence for relationships."
Another Redditor admitted their was no logic behind playing away from home and that they were merely thinking with the wrong part of their anatomy.
They said: "Feels good in the moment then regrets later. Why would I risk so much for such a stupid fleeting feeling?"
Agreeing, a user repeated that there had been no logic behind their actions.
They said: "I was 17 there was a girl naked on a bed that said 'come **** me'.
"So I did. Wasn't right, but wasn't thinking either."