And don't tell me "because you could"

I've been chatting with someone I met on CL late last year and we've discussed a variety of things, including the topic of cheating. He mentioned to me in one of his emails that he had cheated on someone before. He is married now. I have asked him if he would ever cheat on his wife and he said that I knew him well enough to know the answer.

So, yesterday, I asked him why he cheated before and why he would ever want to cheat again given the opportunity. No response. No emails, no correspondence at all.

I didn't ask him that question to judge him. I am curious as to what logic, if any, is behind his rational to cheat. I can only assumed that I hit a nerve and he doesn't want to discuss it with me or anyone else. Fine by me. I just hope I opened his eyes and slapped him back to reality however temporarily.