Orgasm

So like I've been sexually active for years now and I legit can not orgasm. Been with different guys and stuff and whatever and it just never happens. I've masturbated, still doesn't ever happen like I've literally tried everything. The guy I'm with now is determine to try and get me off like going down on me but after a bit I just get, not sick of it, but like yeah dick would be good now and I just know I'm not going to finish. Just wondering if you have any tips or pointers or something I feel like I'm missing out hahaha.