I share in a very similar problem. My BF and I have been together for 2.5 years, and in that time his lust for sex has gone down hill. My problem is that he acts as thow having sex is a chore, and when we are "together" it feels as though he is just rushing through the motions just to get it over with. There is no foreplay, and no touching or kissing during sex. Of course I blamed myself. I tried making myself more beautiful, and making his fantasies come true, that didn't work on him, but I know as a women if my man were to go the extra mile to make my fantasies come true, that would be an instant turn on.