Have We Hit A Sex Plateau 😩

Me and my boyfriend have been dating since March 2014 and we had sex constantly the first year and a half; but now that he is gone for school again for the 3rd time to return for college i feel extremely distant and kinda of want to call it a quits. I'm an extremely sexual person and now that he doesn't me on how he used to I feel like a nun. I feel like an asshole for making it about me but now i suffer through sex with him so that he can have some resemblance of our old sex life. What should i do?