Is this normal?

Okay, so my boyfriend and I have been sexually active for a year now. We usually have sex once a week. I have a higher sex drive than he does and I try to initiate sex with him everyday. He almost always turns me down and says no and tells me to get off of him. I respect him and his space, so I just drop it and go back to whatever we were doing before that. But, every night when I go to sleep he stays up and gets off while watching porn, just a couple hours after turning down having sex with me. I asked him if I'm not good or if I do something wrong, and he says no, that sex with me is always really great. I feel really bad about myself and a small amount of resent towards him, bc we don't have sex very often but he masterbates at least two or three times a day while watching porn, ( which, he won't tell me what kind of porn he watches). I feel like maybe I'm not attractive enough and he turns me down just so that he can get off to the porn girls instead. Is this a normal thing with guys? How can I get him to prefer sex with me instead?