To wonder how people who have affairs justify it to themselves?

[CockerMum]

Prompted by another thread but also a discussion recently with a friend who mentioned they have another friend who has been having an affair with a married man for a decade.
If you have had an affair, even if you regret it now, how have you justified this to yourself?

My mum used the excuse "you can't stay 17 forever " as an excuse for leaving my dad for my brothers scumbag dad (who ironically left my mum 3 years later for another woman) my mum seemed to think being with my dad from age 17 meant she was done with the marriage by age 30. I got with my husband aged 17, we are still together and I'm 42 and have just had our 4th child