Just want to give you a hug Katerina!
I know it hurts. I think you are doing the right thing, you know that. I also know, knowing it doesn't make it easier. Break ups are just all around crappy no matter what the reasons are. I think we always want answers, that's a normal human experience, it's frustrating not to get them.
I think he still has delusions of you being there either when he "get's done" with the drugs, or in some other way (thinks he can) manipulate you into being there for him even if he doesn't. His addict mind just works that way. He isn't anywhere near ready to work towards changing. You will have to be the one to dig deep and make the hard changes that will make your life better. It wont always feel as bad as it does now. One day soon it will actually be a relief, once you've gotten a break from the chaos he brings to your mind and the clouds in your heart clear away.
Hang in there, take LOTS of deep cleansing breaths and please keep hanging out here with us so we can keep propping you up. You are doing the right thing going no contact.