Sorry need to rant

So I had a positive OPK late last night me and my husband bd last night and he's away for the rest of the week so this morning was our last chance this fertile window how are we supposed to conceive when he couldn't even get hard after 20 mins of playing I just said forget it and got up. This happens a lot o try and help him relax and not put too much pressure on but this doesn't seem to make a difference. I'm so frustrated just now sorry just needed to rant