Honey, this is awful. Sex should not hurt. I am a little hesitant to recommend breaking up with so little information, but it seems to me that you risk long term trauma.
My bet would be that, unless there is something physically wrong (and I would definitely see a gynecologist, if you haven't done so already), you could learn to like interocourse in a wide variety of positions, but it would require a very different approach from the one your boyfriend is taking, a very gradual and gentle one. There are a lot of kind, considerate men out there, no sense in waisting time with one who isn't.