Is it normal my boyfriend gets too nervous right before he orgasms

This is so embarrassing in all honesty, I’ve never quite made a post about my actual sex life on this website but I need to hear some honest opinions. My boyfriend appears to ENJOY sex (mostly oral, if that helps any), in fact initiates it 90% of the time, but once it gets to the point where he’s about to cum, he just sort of gets flustered and stops. Like, I can tell he feels really good and he even starts shaking, but he then sort of turns away and pushes me away, so of course I stop. I’ve tried to ask about it but he just says I made him feel good enough or something along those lines, which I’m not even sure of the meaning behind that. I thought it was like something kind of cute at first, like he’s maybe embarrassed about orgasming too quickly (which I genuinely don’t care about I just like seeing him in pleasure), but he just doesn’t let it happen. I’m sure if he wasn’t into it in the first place he wouldn’t even start it, or wouldn’t let it go as long as he did right??? It’s just sort of off to me. Is this something normal, and what reasons could there be for it??? Is there something I’m doing??