Isn't it frustrating!!! I've been there and most of my problem was from birth control pills. Either too high in a certain hormone or on it for too long. And up till just recently I was so paranoid about getting pregnant that I just couldn't get in the mood or enjoy sex at all!! But I got my tubes done a few weeks back so that has taken a lot off my mind in that department. But I'm also tired all the time and hubby doesn't understand that I'm up 2 hr before him during the week, take care of my 6 yr old, chase a 10 month old all over the house, keep up with the house and go to bed when he does. He gets way more sleep than I do a week and probably doesn't work half as hard as I do!!! You didn's say what your condition was that is keeping you from getting frisky but all I can tell you is comunication, comunication, comunication with your man!! When you feel sad about it, let him know, tell him you love him all the time, get him to open up to you about how he feels about the whole thing. Try to find other ways of spending that time together-back rubs, snuggle during a movie. For some reason guys think we can be turned on with the flick of a switch like they are- try to get him to fool around more, go to an Adult store (if you don't have any, I know of a website you can order from) together and get some message lotion or something silly to use together. But you two just need to be open and honest with eachother with your feelings, that is the most important!
Good luck
S.