I'm so sorry you are dealing with this. Agree with the PP though, this is not a topic for Facebook. When emotions are high, it is easy to say and do things we might later regret, and posting this publicly will not help the situation at all.
Is it at all possible your DH feels the sexual chemistry isn't there b/c of the pressures of TTC?
If counseling is an option, then maybe that could be explored.
Again, I'm sorry.