Hiya,
Sounds really tough - it is surprising sometimes how these things affect our DH/DPs. My DH has found it a bit difficult I think as he is used to us just doing it when we feel like it, and recently I have been a bit more "demanding" - so when he feels under pressure it's a bit more difficult to perform, so to speak.
We have now agreed that I won't tell him about when I'm ovulating, etc, and we will just have sex regularly (i.e. every 2 - 3 days). That way, he doesn't know if it's for the purposes of TTC or just for fun (and of course, I know it should be both!). Sounds silly to be pretending not to know, but he said it helps (and I realise some guys are the opposite - different things for different people and all that).
I don't know if this will help, but maybe you could say to him that you'll both forget about it for a few months, and you'll just have sex for fun when you feel like it, and can go back to tracking fertility at a later date. You could introduce a "date night" - one evening a week where you do something nice for each other - maybe take it in turns - so one week he could make you a special dinner and give you a massage, the next week you take him out to the cinema, and so on. That would take the focus back to you guys and your relationship, and hopefully that focus will make him feel more relaxed and able to get back in the groove.
I realise of course that this is all easy stuff when you have all the time in the world and loads of patience, and that in reality it would be really nice to make things instantaneously the way we want them to be, so aside from everything I put above I just wanted to say big hugs, as these things are always emotional and sometimes draining, and it sounds like things are tough right now. I hope everything improves as soon as possible.
xxxxxxxxxxxxxxx