Ugh! Help.

My boyfriend and I rarely have sex. And it's my fault. Because I never am in the mood to have sex. I'm always stressed and tired and I always have something holding me back but I never know what. And it's sorta taking a toll on our relationship because it makes him feel like he's not manly enough or that he doesn't turn me on anymore. When it's always been like this. I've never wanted sex all the time. And I hate myself for not wanting it. I can't figure out why I don't want it though.