BF does everything perfectly and yet....

My boyfriend and I haven’t had SEX sex. Meaning no penetration (not with his y’know that is). We’re waiting until marriage for full blown intercourse but here’s my problem. I can make myself orgasm on my own within a couple minutes. When I get with my boyfriend? I can’t. And I don’t know why because he does exactly what I do on myself and he moves how I ask and it feels good but for some reason I just— don’t orgasm. And I feel so embarrassed and bad about it because I don’t want him to think it’s his fault cause what he does feels SO good. What could the problem be? Any advice? Am I just too in my own head and if I am, how do I get out of it?