Should I date him or will he make me jealous?

In my last relationship, when Boy 1 and I first started talking, he would often mention his ex (she broke up with him, if it matters). These comments were either neutral or in a positive light, but not negative. Before we were dating these comments didn't really bother me, although I did get the feeling that he might not be over her, because he brought her up so often. But they were no longer friends (nor Facebook friends), and they didn't talk, so it wasn't a red flag to me. However, after we started dating he used to throw her "perfection" in my face during arguments when I did something wrong ("She would never do this to me!" type stuff). Eventually when he got mad he started telling me things like how he regretted losing her, she was the one he supposed to marry, etc. It gave me extremely low self esteem and made me very jealous. Even though he didn't talk to her anymore and told me that he didn't mean any of those things when our fights were over, the jealousy never left me and eventually we broke up. I told myself I would never again date a man who talked to me about his ex like that.
Fast forward to Boy 2. We aren't dating, just talking. He told me has no desire to be with is ex again, is glad things are over, all the things Boy 1 hadn't said that made me feel like Boy 2 is a keeper (Boy 2 broke up with his ex, unlike Boy 1, if it matters). However, the longer we talk, the more I'm seeing that he brings his ex up with the same frequency as Boy 1. His comments about their relationship are either neutral or negative (Not in the "She was a huge *****," kind of way, more "It was a mistake I'm learning from," kind of way), but he often brings her up in the conversation when there was really no need to (If I bring up a band I like he may say, "My ex liked them too," or something). He is still Facebook friends with her and still texts her. They live in different states so they don't see each other, but I don't know if the fact that they still talk is something I should be worried about. They were also engaged, and it would break my heart if we ever did start dating and he one day said, "I should have married her instead."
P.S. He is 6 months out of the relationship and we have been talking for 3, so is this just normal "coping from a breakup" talk? Would I be making a mistake if I did date him? I'm also afraid that I may now be prone to excessive jealousy even if I shouldn't be due to my past relationship.