Any psychiatrists here?

I want more facts than opinions though those are welcome too. Idk where to start. I met a guy. He seemed perfect. Consistent. Everything that every other past loser lacked. I fell in love. We were talking about marriage. He proposed. Then he tells me a secret of something he did years ago when he was 19. He was 56 when we were dating. He's had past wives that know about this too & they still married him so I thought well, then it must be fine. It was soooo many years ago. People can change. It bothered me so much though to where I seriously debated ending things with him. I was torn. After some days, I decided to stay with him & not judge him on his past. But this particular thing isn't just anything & it was his reasoning behind it that really bothers me. Please tell me your thoughts. Here it is. He went to prison for 3 years for sexual assault. He won't tell me if it was just attempted or there was actual penetration. He said he was a violent person who loved violence. He was looking at a magazine or something one day & saw something about rape. It intrigued him. He wanted to try it to see how it felt. To see how it felt to force himself on someone with them resisting. That was the reason behind it. He said he held a knife to a girls throat. He won't tell me anything else though. He said he became a Christian & changed while in prison. Said the guard said he would be back. They always come back. He said not me. He's never been back since for anything. While we were dating, he said he thinks it's ok to hit a woman back. My question isn't whether you would be with this guy, my question is what are your thoughts on someone like this. Their mentality? To do something like that & with a reason like that. This is my main question. The reason itself. To me it seems like a mental illness and can someone really change from that? Another thought hit me..do you think he still has these urges & he's just been harboring them all these years? I'm afraid he might explode one day. He loves to play the victim in everything too..like he's the one being abused. He's a narcissist. EDIT: I want to reply to comments so bad but really want to stay anon. To answer the question of his previous marriages, he blames them. Basically says they all cheated & that's why it ended. I don't buy it especially with him saying it's all their fault & doesn't take any blame for himself. His 3rd wife, he says he only married for money which I really didn't like hearing. He has horrible character. He put on a good act but I've seen him for how he really is now.