I can’t finish/orgasm

Ive never been able to finish or orgasm. If I masturbate it’ll start to feel really good and it’ll just stop and it always confuses me. It’ll do the same thing during sex. When my boyfriend eats me out he uses his tongue on my clit and fingers me at the same time and it makes me feel like I have to pee and it just stays like that. When everyone describes orgasms and stuff they make it sound amazing and I really want to experience that. Any advice?