To the best of my knowledge neither ydador any of my brothers have cheated.
Same with male friends.
I work a corporate environment with mainly man and it involves a lot of after work, some overnights etc. Ime, the majority, say 75% don't.
Of the 25% who do, about 20% are serial cheats. Every opportunity, not fussy with who etc. 5% I think are surprised theseves even, usually opportunism rather than going looking for it.
Contributing factors or the most common cases I see - married way too young, got married due to unplanned pregnancy, mismatched spouses - unbalanced relationship (doesn't matter if theyare carrying the bigger balance or spouse is), under pressure or failing at work- cheat to prove something to themselves - ie might not be able to get the promotion but they can still pull/massive but delicate ego type.
I've only know 2 cheats in my life where I was completely surprised. Rest were predictable. Not naive enough to think I know all the cheats - there must be some discrete ones who are good at it.