Hi OP,
I will give you my personal opinion, and I really don't want to offend you in anyways its just my perception. The decision will always be yours.
I think you should stay away from him for several reasons:
1. For your own respect
2. TOO MUCH DRAMA
3. The guy has a big mouth obviously spilling all his personal life about his ex or whatever to you when youre not even suppose to know about that. Would you appreciate if you were his girlfriend and he would be complaining about you to one of his female friends that you dont even know?
4. The guy was never into you, it sounds like he thinks that you are his safety jacket when things turnout bad with his ex or so.