First of all, big hugs.
I am so sorry you are going through this. Is your DH seeing a counselor? Does he plan on seeing one? This may be hard on you but maybe he just needs some time alone to sort through some personal things. He can't be there for you if he is truly sick but this may not last forever. He needs to help himself and then maybe things will turn around. I don't know what else to say but I wish you lots of luck and love, make sure you surround yourself with people that are your support system while you are going through this.