does suze matter?

my bestfriend and i finally decided to be in a relationship and we have been friends since the fourth grade. we finally had sex but he isnt very big and it wasnt to enjoyable. I didnt feel that connection you do when you love someone and yes I do love him. I dont want to be selfish but everytime he tries to get something started I push him away because I am scared I wont enjoy it again. what do I do? HELP!!!!!