I hear you guys. I am one who would never cheat, especially now that I have gone through this. However I did cheat in college. Yeah sure, it doesn't 'count' because we were dating, not married, which is a different level of commitment, but still, it did count! Sometimes I wonder in some stupid supersitious way if his cheating on me now is some cosmic payback...but I know really, you can't compare being 19 in college to being 30, married with kids.
But yeah, I see how it can happen. You hang out with a coworker or classmate, you have some 'sparks', you joke, laugh, they make you feel good about yourself, and there is a connection. The thing is you can choose to feed that connection or starve it. People who think they can 'handle it' are usually fooling themselves....