Blowjobs

Help! Every time I give my SO a blow job he always interrupts After like 20 seconds and just goes straight to sex!!! I'm afraid I'm doing a horrible job!!! But when we are having sex and he pulls out to cum in my mouth I always suck his dick and at that moment is when he moans and goes crazy over head. Do you think I'm horrible at giving head? And the only reason he enjoys it at the end is because he's at his peak?!?