Billionaires and wealthy people (celebrities, athletes, etc.) cheat on their wives. Almost all of them. (I would say all, but I am leaving room for error.) It doesn't matter how wonderful their wives are, they do it because they can. And it becomes a habit.
The guys that swear they never would basically just don't have the opportunities. They work and live near the wife, in a small community, they can't afford it, etc.
Try being Tiger Woods or John Bon Jovi, always far from your wife in a location with few friends, with beautiful women throwing themselves at you on a daily basis. You will crack.
When Trump was young, rich and famous, he most likely had beautiful women hitting on him daily, and got used to it. That's the way it is - all around the world. Some cultures even accept it and accommodate it.
In my experience, those "good guys" who hold out longest tend to go the most wild when they finally crack.
You can be pretty sure that Melania knew the score when she got married.
