I Can't Orgasm!!

I've never experienced anything other than a short climax by myself. I've been with my boyfriend for two years and the fact that idk what to do to get myself to orgasm is a big problem when it comes to him pleasuring me. he's really determined to get me to orgasm but everytime we do anything , even for long periods of time, I can never get off. And that makes him upset and feel like he's a bad boyfriend. Please share your masturbation habits and how you get off. it would mean the world :(