I have to admit, I can understand where you're coming from, but consider this scenario: You've known him a number of years, everything has been sweet, you got married, had a few kids, and then found out he'd spent time in prison. It's not as simple as just writing a Dear John letter and refusing to answer his calls. And what if he doesn't want to tell you not because it's anything overly bad - oh dear, he forgot to pay some fines and took a jail sentence instead - but because he's terribly embarassed about it? There's always more sides to every story than just the one. But yeah, I have to admit, I'd be VERY suspicious of anyone that had spent time in prison and refused to explain why. A simple explaination can solve a lot of problems.