I did manage to talk my DH into baby dancing afterall. Of course all he could do was lie there, which isn't the best position for baby making, but much better than no sex at all.
I had another acupuncture session this morning. She said that I should be right now, but I can come back next month for a session or two if I want (and haven't fallen pregnant by then).
She said that my problem wasn't fertilising the egg, but rather in implantation and/or holding on to the baby. That's pretty obvious with a luteal phase as short as mine. Imagine if nearly every month I have been getting pregnant but my body keeps dropping the fertilised egg! Arrgh how frustrating.
Fingers crossed that the acupuncture (and vitex) help lengthen my luteal phase long enough for the pregnancy to hold (if it occurred of course).