It's hard to know for sure how many cheat, and I suspect the real numbers are much higher than what the statistics say (since people won't always be honest about what they do or did).

I suspect people are afraid of getting caught, mostly, and I read that most cheating happens when being away on conferences and stuff like that. Whenever there is no chance that anyone else finds out who meets together in a room.

But yeah, people won't like to think about these things since it's scary as hell if you are being cheated on.