Oh honey, my ex was like this almost EXACTLY to a T. We started dating and he would drink 2 tall boys in the shower, 1 on the way to work, on his lunch break he would go buy a bunch of the small samples of liquor and then drink until he nearly passed out at his second (serving) job. He would drive home drunk every night and I'd drag him to bed. He started bringing other girls home and even though I hated it, I still felt the obligation to help him, especially when he lost his job. Whenever I threatened to leave, he'd "attempt" to kill himself. He broke me in so many ways that my mom cried whenever she looked at me after I came back home, but looking back at it, the best thing I did for him and me was to leave. I was enabling him by taking care of him. He was abusive and manipulative and he was never going to get better while I was around.
You need to take care of yourself. How he reacts and what he does in response to you leaving is HIS problem. You didn't force him to do anything. I hope that you go to an al-anon group or look into counseling for the damage he's done to you. You deserve so much more than this.