I'm still fairly newly sober so I don't have a whole lot to offer on the addiction part of it.
I agree there may be some co-dependence issues there, no offense.
If one of his "issues" he needs to work through is his ex, I'd bear in mind he was not likely totally emotionally "IN" the relationship with you. Furthermore, a lot of what you are relaying that he says, sounds like romanticized bullcrap. (Sorry if that sounds crass).
She is the ex that "put up with him". There is a very real possibility you may be the ex that "took care of him" in the end.
If it were me, I'd RUN.