I had to come look at your post after you compared our situations. I've been where you are, and it's one of the hardest things I've ever done.
From your post, I'm assuming you're still in contact. This is something I'm struggling with right now, but one thing I do know is that you can't help him unless he wants it. My addict was using both meth and heroin and had been clean for almost a year until he started drinking (he's still not using drugs, but it doesn't matter does it?) Unless you've got strong restraint, you "being done" won't last long unless you really acknowledge how bad he is for you, no matter how much you love him. I won't tell you what to do, cause that never worked for me, but please be cautious with your heart. If all the red flags are going up, telling you to leave, then that's what you need to do. There's no doubt there's love in this relationship, but take it from someone who has been there, sometimes love just isn't enough, no matter how desperately you want it to be.
My heart aches for you, hun. I know how hard this is and I hope the best for you and your addict. Just remember, he's not the only one you need to take care of. You come first!