Hello TiredGirlfriend, it always takes great courage to make a comment on the forums, but really pleased you have.
A person who needs to drink alcohol and smoke marijuana may be doing this for several different purposes and anybody doing this will have their own reason, whether others may know or it could be hidden and that may not be easy to find out, however, it's up to them to decide whether or not they want to stop.
You are not responsible for his own actions if you do decide to leave him, but once someone refuses to get the help they need, the only option is to leave.
The act is a call out for help and once released he then denies any treatment you can call in Vic Mental Health First Aid on (03) 9079 0208, other states will have similar phone numbers to contact.
You can also copy and paste this in your browser 'Getting help from crisis support and telephone counselling services', this may provide help for him.
There are three issues here that are concerning, and I'm not a doctor, but his drinking/marijuana, how he is feeling mentally and his temper, all three combined can make your life very unpleasant.
Can I also suggest that you see your doctor and wonder how you felt when you weren't living with him, this may help you to make your final decision, but would really like to hear back from you.