Why do some men with strikingly beautiful women cheat? Charlie Sheen, Tiger Woods, the list goes on?

Sometimes the "other woman" is actually plain or downright ugly. None of the ladies Tiger Woods went out with can hold a candle to Elin. What can be hotter than Denise Richards? Don't these men realise what they are doing? Or there are girls more beautiful than these?
What do men on this group this?
What do ladies on this group do to keep their men from straying?

Why do some men with strikingly beautiful women cheat? Charlie Sheen, Tiger Woods, the list goes on?
Post Opinion