Cheating...it's a choice. It doesn't make you a better person because you don't cheat. Of course, I know guys who cheat and are pretty good people, then I know dudes who don't cheat who I think are jerks...like jerks.
I say, it's a broken promise, but when you are in a relationship it's unrealistic to think you're never break their promise, or break a women's heart. You don't have to sleep with another girl to break your womens heart, you can just generally be a scumbag to her. "I hit her in the face, but I never cheated on her" " I made her sleep outside, but I didn't cheat on her" "I crashed three of her cars, but I didn't cheat on her" " I got her locked up, but I didn't cheat on her."
Then, there are some girls who wouldn't even mind. If my wife cheated, one night stand, nothing brought back, I would care a lot less than if she was constantly hanging out with some dude, talking ish behind my back, eating, having the dude around my kids even though they are not sleeping together...there are much worse things in life than my wife cheating...it's all about perspective it's not a pass, but if a one night stand every few years is her only drawback (which includes she never bringing anything back, because that is a completely different problem, so don't go there) then I'd have to say, Id be ok.