Why does this guy do this to me?

This guy i like always touches me. Like once i was running towards him when we were walking together and he started giggling and said start jumping and i was like wtf why? i didn't say that though. And once he slipped my hand up my and grabbed them to. And he's pinched my . And once i slide my hand across his crotch by accident cause i was trying to get papers from him. And he said mmm you like touching me there huhhh. And i was like o . o wtf No! And he groped my side but since we were getting on the bus when he tried to i stepped forward really fast. idk why he does this to me. I don't think he likes me because im very ugly and fat. So i think he just likes me because of my . But he did say i look skinny and pretty. But i was like really... -.- I guess all i can say is why do you think he does this to me? And he's dating someone! So i have no idea why he does this.