I am in a similar situation. I don't know what the answer is but I send you my prayers that you can find your way. It may be that by leaving him and helping yourself, you will be able to help him as well.

Heavenly Father, be with this wife who has been struggling with holding this marriage together by herself. Lord, she has so much on her plate which she must handle! Give her the insight of what to say, and do!!! Guide her through this valley. Send your angels to encamp around her. I pray that you supply her the strength to carry this heavy load. Let this husband hit bottom, so that he cries out to you for your help. Let him be so low that he becomes very serious about getting the help that he needs to over come this drug addiction!!! For this I do Pray, in the name of our Holy Father Jesus, Amen!!!