I disagree with this, because as a man You are entirely in control of your emotions/impulses.
But also, we don't always know why a guy cheated. I have 2 uncles that the family recently found out cheated on their wives. When all the details finally came out, i sort of understood why they did it. I still don't agree with it though. It appears both men were not getting any from their wives, and even though they kept asking for it, the wife didn't think the man would cheat on them. Only one couple divorced, the other is still together after working things out.
Bottom line i think like this, if you're gonna cheat then just break up with your current partner. There's no need to be a scumbag and betray the trust they gave you.