Boyfriend doesn't wanna have sex with me?

Our relationship is great (we've been together over a year, live together, and love each other very much) BUT, he never seems to wanna have sex. I would like it once a week at least, but we go a month or more without. I'm 21 and he's 22. He's not gay and isn't cheating on me for sure. My self-esteem has decreased immensely. I just want him to want me. He says it's not me, it's just he doesn't think sex is that important. But I do think it's important. Is this a deal breaker? What should I do? I'm sad....