I had a similar situation. Unfortunately for me, he began a relationship with an ex girlfriend who he used with and got sober with. I was told he was only seeking guidance from her as she became sober a few years earlier. I never knew whether it's true or not. He then cut me off from his life. I recently learned that he and this girl have been in a relationship. The thing is, you cannot control another human being. He will do what he wants to do. You have no control over that. You do, have control over yourself and your own life.