Hi, and welcome--congrats on your sober time! I'm six years sober, myself, in AA.
As I said to someone else here, recently, it really doesn't matter if it's his alcoholism or his basic personality, it sounds like he's lousy relationship material. I sometimes think we feel compelled to go back with these guys just because it seems like if we try HARD enough we'll figure them out and things will finally be "normal". Sort of the same way most of us alcoholics were so stuck for a long time on getting a handle on our drinking, if we did this or that. It's a desire to control a situation that is beyond our control.
Hugs, don't let this derail you. Sounds like your head is screwed on right. I'd throw this one back, though.