Guy cums too fast

Hey guys so I currently have a sex buddy. We always have good sex, it feels good but he cums too fast. Literally he cums in like 5 mins. The other day we had sex he stuck it in and like 2 mins later he came. He doesn't jerk off or really watch porn he saves it for sex. Do you think this is the reason why he finishes so fast or do some guys just cum fast?