I can't orgasm! What can I do to fix this?

Well, I've beendating my girlfriend for 10 months and she's never given me an orgasm, nor have I ever had one. She is starting to get upset by this and feels she is not giving me enough even though I'm perfectly content with her. She has gone as far as giving me head and has gotten no reaction from me. I need a way to make it easier to go off... Please help!