You are not abandoning him, you are getting on with your lives. He is choosing not be part of your lives through his refusal to get help. You can not change his lifestyle choice. He can not change your lifestyle choice unless you allow it to happen.
I would suggest checking out al-anon or nar-anon meetings where you will meet people who share their experience, strength, and hope in dealing with similar circumstances and how they have come out the other side of the heartache and anxiety.
You deserve peace and serenity.