Did you talk to him about what you experienced when he is using (now you know that he is using). Did you explain the verbal abuse?
An addict may be able to fix themselves by themselves but that wasnt possible for me. Maybe he can. Im not sure that making a decision after you talk over the phone is the most thought out reaction. Yes, I know you are upset, unhappy, etc but I think a face to face conversation might be good. Maybe in a park at a picnic table in public so you dont have to be afraid about physical abuse. If he starts verbally abusing you, you can walk away.
But thats just my opinion. Im not one to make a decision without at least exploring options and having a heart to heart talk.