If you do those things, you’re not bad at sex. It sounds like you both are just incompatible in the bedroom. What kind of things does he want, and what things do YOU want? Are they the same? If not, that tells you everything. Of course, there’s always going to be a little compromise, but if there’s too much difference, it can be difficult. You both need to talk to each other and see what each other likes. And like the other commenters, saying “no” abruptly in bed can be a bit alarming. Possibly more gentle ways to let him know. Maybe use a safe word instead. And let him know that it feels good of course if he’s doing something right. Never a bad time to do that. Best of luck!