Of course, we all know that while men and women are both capable of cheating, it's often the guys who have the biggest problem keeping their belts firmly buckled. And we all know that no matter who it's with, why it's done, or where the after-hours canoodling takes place, cheating is-most of the time-the ultimate relationship death sentence. But instead of dwelling on what happens after the cheating takes place, one of the ways to perhaps prevent infidelity is by knowing a little bit about why men stray. I'm not offering them as excuses, merely explanations as to what happens in that brain (and other body parts) of his-in hopes that you might be able to prevent it. Here, the top reasons why men cheat: