What an awful place for you to be in, I am sorry. I have also been there, and know many women faced with similiar choices as yours.
I know you love him and hate to see him hurting but the reality is you cannot help someone who does not want to help themselves. I absolutley think you should help point him in the right direction if you can. At this point,if things are as diar as they sound, I would demand that he see a proffessional to help assess the situation, and offer to set it up and take him there. If your husband is unwilling.. I fear you staying in that enviroment will only lead to more despair for the both of you. Your husband is unable to help you do what is best for you, your needs are not even on the radar.I think you should think deeply about what YOU need to be ok.
It sounds like your emotional and spiritual health are in grave jeporady. This is not good for anybody. Hang in there. One last thing..you are not his HP and therefore cannot be ultimately responsible for his choices or well being. Do not place yourself in a role you were never meant to fill. He is an adult, and suffering he is, but he is the only one accountable for his actions or lack of. His higher power has freedom for him, but it is something only he can decide. I wish you could make everything all better, but you can't.
Lots of love :praying