Welcome, Allie! There are some strong similarities in our stories. I fell hard and fast for a man in his late 40s who pursued me hard for many months. I finally gave in, having no idea he was an alcoholic and pot addict. I was clueless about the addictions for a long time. The first time we broke up, he ended it out of the blue, telling me he wasn't good enough for me and that he could never be the man I needed him to be. I was devastated. He came back later, professing a commitment to sobriety, and I tried it with him again. We danced the alcoholic-codependent dance for over 5 years, making up and breaking up, until I finally learned to accept that no matter how much love we had for each other, he loved his addictions more than he loved our relationship.
I'm sorry you share outside space with him. That will be very, very hard. My xabf lived less than a block away, and for a few months after a break-up, I watched another woman come and go from there. It nearly killed me. I didn't want to see it, but had no way to avoid traffic patterns with them.
You sound like your head has a good grasp of your reality. How is your heart? How is your support network? I hope you have good friends to spend time with, places to go, people to see. If you are serious about remaining separated from him, my best advice is not allow yourself to have any contact with him. Period. Because if he follows typical alcoholic behavior, there will be a point where he will contact you again. He will want to know if you're still in anyway feeling anything for him. The alcoholic ego typically needs that, and especially if he is the charming entertainer type. If he sees that you are not giving him attention, he will probably come looking for it. Be prepared for that.
This is a good time to focus on yourself, and start asking yourself some questions. Learn why you ignored the red flags in the first place. I was good at that too. I would ignore entire parades of red flags sometimes. Read the stickies at the top of the forum pages if you haven't already. Loads of awesome information and insight there. Keep posting, and welcome to the family. There are good people here who have been exactly where you are!