Is it normal that he can't orgasm sometimes?

We've been having sex for about 2 months and it's been really hot. We have sex every day we see each other which is about 3 times a week. However, sometimes he can't orgasm, especially if we do it two or more days in a row. He is very turned on (hard) but just can't cum and I think he feels pretty frustrated and unrelieved. This has happened with oral sex as well (and I know I'm good!). I love sex and orgasm easily and every guy I've been with has too! Why is this happening - performance anxiety/ too much pressure, not turned on enough, me?

Is this normal?