Relationship Advice

For a couple months now bf &&&me haven't been having so much sex like we used to, every time I try to hint to him I want him he always makes an excuse his belly hurts or his back or some thing &I want to know of maybe he isn't into me anymore.. Due to his past relationships I'm no where near to those skinny girls. I juss want to know if maybe I'm in the wrong relationship &he juss doesn't know how to end things..