TTC, SO Having Trouble "Performing"

It seems that during that golden fertile week my husband has difficulty keeping it, well, up. Our sex life is fantastic except for the one week I need it to be. I don't let him know my cycle schedule, he does want a baby, and he has a clean bill of health. I know it's anxiety or stress, mostly because he's anxious about it going flaccid and because of that it does.

Does anyone have similar issues? Advice?

I have exhausted all options I can think of. We usually have sex 3 times a week, on average with the exception of that one week which will drop to only once. I'm not angry that it happens, I just try different things but it just does not seem to be helping. He masturbates regularly but even that doesn't happen during this week.

*shrugs and sadness*