Have you seen Hammer's video about Letting People Go?
https://www.facebook.com/photo.php?v=573490496073256
Its brilliant. And it makes perfect sense. You will get past this, you will do better, be better, grow and learn and move on in life while he is stuck in his rut, in his cycle, going nowhere fast. Focus on you. It hurts and there will be days where you want to just scream in frustration at the ridiculousness and unfairness of the whole thing. Don't let his chaos drag you down, FOCUS on you. You seem pretty put together, I think you are going to do just fine. Let go of this guy, do a little work on you, and one day, you are going to find someone a hundred times better. I agree with everyone else, you are gonna be much better without the drama that comes attached to an alcoholic.