Welcome to SR, though sorry for what has brought you here. I think, actually, you're miles ahead of where I was when I was in relationships with A's (addicts/alcoholics). I then BECAME an A (crack), and it did take me hitting my bottom before I chose recovery.
I can't tell you whether to leave or stay, but sounds like you've been on this merry-go-round before and want to get off. I came here, an A, looking for support. I was drawn to THIS forum because I'd always chosen men who had "issues" - alcohol or crack. I wanted to figure out why I'm drawn to unavailable men (if they're using, trust me, they're unavailable) and get beyond that.
Still haven't figured out the "why" part, as I wasn't raised that way, but I have gotten to a point where I know what I don't want in a relationship, and an idea of what I do want.
There are a lot of people here with some great ES&H (experience, strength, and hope) and it's kinda slow on Sunday's, but you may want to read some other posts. I did, when I first got here, and found out I wasn't alone, and that was very comforting.
Hugs and prayers,
Amy