i just read your post and i have a couple of questions.
simplest first: what does DH stand for? i'm assuming the H is for husband.
secondly, you mentioned that you and H discussed different possibilities and that you ruled several things out. what you don't say is what explanation he did give - if any - for decreased sexual interest. did he give any explanation?
third, did you talk about the possibility of erectile dysfunction or his fear thereof?
lastly, can you give me - if there is such a thing - a description of a typical encounter in which you have wanted to be sexual and he hasn't? how does the situation play out?
i am middle aged male by the way. i don't know if that gives me an advantage in helping you, but perhaps it might.