Along with a lot of people who are not executives, and people who were not executives at the time and went on to become executives. Like it or not cheating is relatively common, our species is not strictly monogamous and the evidence can be found in male anatomy (read about it if you are interested, particularly in comparison to Chimpanzee and Gorilla anatomy).

I am not saying this as a defense of cheating; it is just a fact that people cheat on their spouses, regardless of the moral implications or how "never cool" it is.