I can't orgasm or cum?

so I've had two sexual partners in my life and they have both been different boyfriends of long relationships. I'm only 17 which is young I know, but it makes me wonder! my first partner was just awful but I made a HUGE upgrade and let me just say, I can't even.😂and can I not cum or orgasm because I don't know how?? because he's AMAZING and all the time I really want to and have the urge but I just can't! it kinda makes him feel bad I think because a partner of his before could and I feel bad that I can't. I don't want him to feel like he's bad because he's not. anyone know the science to this?