Found out new date has a dark past... advice

[int84]

Hey Everyone,

27 year old male- I've been trying to take the dating thing very slow... going on 'dates' with a few guys... no kissing or anything... just to see who I like best. I messaged a guy on a popular dating site, and he seemed generally interested in me. We talked for four hours each, two nights in a row. Our first date was pretty nice- he even reached in and kissed me. Even though I was trying to just take it slow, it was a pleasant surprise. Right after the date, he texted that he took his dating profile offline, and that he really liked me. We met up again shortly thereafter, and due to the romantic feelings at the time, fooled around. I normally don't move that fast. He proceeded to say that he still really liked me, and he was off the market- doesn't share well. Should that have been a red flag?
Excited about my new prospective, I did a search for him online... turns out that he has a dark past in the area of 'non-violent' jailtime. I was shocked. Upon calling him up and out on it, he said he doesn't like to discuss it, and it was a good time ago- is working very hard to forget that and better himself. I'm cool with forgiveness, and all, so I understood. He messaged me that he was an emotional wreck- crying and needing his friends to talk to him, after I asked him the question about his past. We saw eachother another time... to which I still feel he is a nice guy with a lot in common (media and humor-wise) with me. We are supposed to get together tomorrow... however, I am now having doubts. Should I have tons of alarms being sounded in my head right now? He likes me way fast after only a few dates... has a past he doesn't want me to discuss... cried when I asked him about it... said he doesn't share well.
What are your opinions? I have a very big heart, and I feel that trying to break it off would be hurtful. Should I give him more time... or should I look out for my best interest?

Thanks!