DD was two years in the making, and I'm sure a lot of the problem was that DH works away for two weeks/home for two weeks so it was really hard to time things. He used to leave for work at 4am and there were times I knew I'd ovulate in a couple of days so I'd get him to wake me at 3am to get one in before he left! lol
In the end, we didn't conceive until our honeymoon when he had time off (obviously) and now we are faced with the same problem again so he has re-organised his roster to be home for the important time of the month.
So I guess my point is, the 'zombie-3am-totally disinterested-sex' didn't work for us, but the roster change did.
Wish you luck!