Dear CaringScared, I am in a similar situation like you. I guess I can call myself lucky because he ended our thing the moment he told me he is a drug addict. Yet, I feel like a rabbit that keeps standing in front of a snake instead of running away, since I can't let it go and "I really like the person I believe is inside". So, I definitively, feel for you, especially because you already endured much more than i had to.
I don't really know what to tell you, since I still figure things out by myself, but I wanted to let you know that you're not alone. Hang in there, you do the right thing. Feel free to reach out, if you want to talk !
(((hugs)))