Sorry i probably wasn't being explicit enough. I'm not tryng to say that its an excuse for cheating in a Premeditated way, as sanity, logic and morals will hopefully give you enough of a chance to contain your urges. However in a spur of a moment situation, it is easy for an infatuation or lust to take over from more long term intrests. It can happen to anyone in many situations (not just cheating) and partly explains why people do things they instantly regret.
Again I was not trying to say that this is an excuse for cheating I was just trying to point out that if some one cheats it doesn't mean that they don't love the person they are cheating on.
and the referencing thing- i knew i would get flamed for that, but i didnt want to start spouting knowledge without backing myself up.