m(18) cant cum from masturbation anymore?

i(m19) have been only having vaginal sex sometimes i put it in my girlfriends butt and get orall idk all that but for the past 8 months i havent really masturbated much because i didnt feel the need, today i tried and like a hour went by and nothing, do i actually need to be with someone to finish now or like? also sorry if i sound retarded idk how to type good