It’s a difficult situation you are in living across the street from him. For the last year what has your therapist suggested you do? Is it possible for you to move?
My best answer to your question “why am I still in love with him?” because you have not let go you are still holding on to something, hope, what ever it is you have not let go.
Something I learned was when my bf relapsed and we broke up and I said things like “he’s worse since we broke up” my codie self was taking responsibility for his actions and kept me emotional involved to him.
If you are some how feeling responsible for his drinking then thought feelings are keeping you emotional tied to him and preventing you from letting go.
I also attempted to date while my feelings were still so strong towards my ex and all that date did was make me feel guilty as if I was doing something wrong. I was no where near ready to date.