Well your mental if you want to stay with him. Ive got a coke problem. But im using about once a month. But it makes you dissapear for days. I dont because my gf will kill me. But being on that stuff for days is mental. And you do stupid things.
And its a typical story that. He dont want you, but he dont want anyone else to have you and gets back with you.
If you want my honest opinion. If hes not admitting he has a problem and is not prepared to change id leave. But i think you should leave now while you have no kids together. You can do better and you will get better. It just takes time. Spend time with friends and family to forget about him.