Ouch. No it doesn't sound to me like you're the one with the problem, except maybe giving too many chances. I've been in a similar situation and while the logical part of me said "fool me three times, shame on me twice" that doesn't do much to stop the pain while you're in it.

He does sound immature or commitment phobic or a combo of the two. But it sounds like that's just the way he is and probably has nothing at all to do with you--I mean certainly there's a reason he is still single 20 years later and it's not about you.

I agree though it's best to move on from this one. All the best to you in your healing.