Helpful criticism in the bedroom

Me and mt boyfriend have been together about 2 1/2 years. Lately my sex drive just hasnt been there at all, likr i seriously never want it. And when we do have sex, its horrible. He cant take any helpful comments without getting all huffy and puffy about it. Half the time, he doesnt do enough foreplay. The other half the time, i swear, he doesnt know what hes doing. Sex is very hit and miss and its driving me crazy. What can i do to point him in the right direction.??? I can be very patient, its just getting hard to want sex at all.