Dear Believer,
As I read your question, what stands out most are your feelings of hurt and confusion about your husband's inability to turn his "switch" emotionally/physically back on for you.  There can be many reasons psychologically, emotionally, or physically that can cause this "switch" to turn off in individuals.  The first step is to ask your husband if he is willing to talk to a professional to uncover what is really going on for him. If he were willing, I would seek out a therapist who specializes in marriage and family counseling. If he is unwilling to do so, explore with him what it could be. In this exploration please understand that he may truly not understand what is going on with him, may feel embarrassed to share with you what is going on for him, or he may be afraid to tell you the truth out of fear of hurting you.  Something like this usually does not resolve itself on its own.  I truly hope he is willing to speak to a therapist and your marriage comes through this stronger and even better.