Loyalty,
Some women just don't orgasm from straight oral. Have you had it combined with some vaginal penetration with a toy and with fingers? And have you had it with anyone you were really comfortable with? If you aren't really relaxed and just letting your body enjoy it and allow the orgasm to happen, it might be a challenge as well. I've been with a few women who didn't mind it but it wasn't how they preferred to orgasm, they wanted to feel a cock inside and have their clit stimulated to orgasm.
But, I'd love the chance too try to make you orgasm orally! 😉