Boyfriend or dangerous other man?

A few years ago I was roommates with this guy, kinda dangerous, pothead, hooked up with lots of girls, anger management issues, lies a lot, always loser jobs or jobless, broke, and borrowing money, but SEXY. And fascinating. We had many mutual interests and I decided to befriend him, and we have formed what is in my mind a deep and lasting friendship. I had feelings for him on and off, but would never let myself act on them because of...well, all the reasons listed above. Then he got a girlfriend and I got a boyfriend and I thought all our issues were resolved, until he began to turn his life around. With the help of his uncle he is on his way to becoming a decent, honest person, and my feelings for him came back big time. My boyfriend is a wonderful man and I respect him, so I told him we needed to call it quits because I was having serious feelings for someone else. So I spent some time with the other guy (he was on the outs with his girlfriend), hooked up with him...and I missed my boyfriend! He was wonderful enough to take me back, but now I’m not sure my feelings for the other guy are completely gone. We have so much fun together, but my boyfriend really is the better man, I just worry that me and the other guy have more in common...and I want to be sure I don’t hurt my boyfriend more than I already have. How do I know which feelings are real? What do I do?