masturbation and sex

it honestly bothers me how long it takes me to orgasm when masturbating, im still a virgin and im worried that when i finally find someone i want to have sex with, they wont be able to make me orgasm because of how long it takes (like 10-20) and ive heard a lot of guys will orgasm and then be finished cause theyre tired and stuff. id hope the right guy wouldnt care and would want to pleasure me too but its just really annoying. ALSO after you orgasm a lot does it get less intense as you have more??