My boyfriend spanks me?

soo i'm about to turn 14 and my boyfriend is 16 During sex he will do certain things that REALLY annoy/ hurt me, but i put up with it cause i love him !!<3 For one the spanking. It actually does hurt. He willl call me a little slutty girl and other witty things and spank me. What the hell? i told him he hurts my feelings but he said he doesn't mean it when he says those things. Another thing is he's obsessed with my bellybutton He's always touching it, fingering, it, licking it and its weird! ive told some of my friends and they think im so lucky? how can i get him to stop without breaking up with him? i love him but its really annoying and spanking actually hurts. why is he spanking me? his ex keeps on telling me that he's using me cause im 13 and easy, but its not true. i just wanna know why he does this mean stuff?