Help please!! Sex life troubles

I have a hard time enjoying sex sometimes because i rarely ever orgasm. Now my boyfriend has a high sex drive and he truly does try to please me but for some reason it just isnt working and pushes me away from wanting to have sex at all since i know the outcome wont be anything. I feel horrible sometimes because i know how important sex is to him and how it hurts his feelings when i dont want to but at the same time it sucks for me too because i have a hard time enjoying it if i rarely ever orgasm. I have never orgasmed from penetration either? Any advice ladies this is really hard one and i would rather say it here than telling peoole of our sexual problems