I'm so sorry for you, but I definitely know how you feel. If only my H could have been/be civil and honest about his feelings, things would be easier for me too, I'm sure.
I suggest moving to Midlife Crisis, because in reality, that's exactly what it is. I still believe when he comes out of it, there will be no other woman on the other side, and he'll have to face his fears/faults/self.