Self Conscious about this Tough Nut

I’m 32 and just started having sex.

The guy I’m currently seeing has come over a few times and we’ve hooked up, only he doesn’t cum every time.

I thought it was a given that guys just get to cum every time. I didn’t realize that they could just walk away without finishing.

He says that I shouldn’t be worried about it. But obviously it is a blow to my ego and makes me think that I’m probably really bad at sex in general. Drawbacks of being a late bloomer, I guess.