I would say, the fact that he continues to use, is enough for you, to keeping moving onwards.
Even though you may still have feelings, and it hurts your heart, do you want to be in amongst that chaos? It's no way to live and you would be back at square one.
Let him go, and concentrate on yourself, and what you want for your life. He can't help you with that.
Just my thoughts.
Much Love
Bute x