Woah thats pretty serious, thats how some marriages break up, lack of sex (ever seen american beauty!?), but you obviously need to have a serious chat with her about it, How old are you both and how long have you been married, its opinion really and i think in a marriage you "need" sex because you need that physical attraction to stay there you cant ever let that die..

Maybe its something you've been doing, maybe you need to spice things up?? tell me more, do you think its something that you've done thats made her feel this way?