He can’t cum?!

The boyfriend and I have been having sex/messing around since April. The first time we messed around, he came, but it wasn’t a lot. First couple times we had sex, he came (he rushed to the bathroom to take the condom off, so I don’t know how much). But that’s it. Handjobs, blowjobs, sex...he never seems to cum. If he does come, it’s literally a few drops (and usually mostly clear). He says it’s always been hard for him to cum and most of the time he doesn’t - even when he masterbates. He says he loves our sex and really loves getting me off, but I always feel so guilty. When we have sex or mess around, he’ll get me off so much, and I hate that I can’t get him off once. I’ve never had this problem. Because of all of this, he says it would be extremely hard for him to have kids. I just don’t get it 😩😩