Should I drop him?

So I've noticed that a lot of girls get some pretty good advice on this app and I just want some other opinions on my situation. So I'm 16, and my SO is 17. I've been with him for a year and a half. He's tried to break up with me three times within that time span. Just this last weekend I went out of town for a science competition and lost and was/am really bummed about it. I asked him if we could talk about it, he told me he was playing his video games. (an ongoing problem in our relationship) He apologized for being that way at 2 AM, I didn't respond all the next day and everything was kind of cool after that. Today we were walking through the halls @ school and he had his hand on my back and decided it would be a good idea to give me a wedgie through my dress that I was wearing. I got super angry and went to the bathroom and fixed it and wouldn't let him touch me after that. And it really isn't the first time he's done something super embarrassing to me while we're at school. It's like he has no respect for me at all. But what made this time different is that I didn't let him touch me after. And so I tried to pull him aside to talk to him and tell him that that kind of stuff isn't OK. Period. But he got really petty and kept walking to his dad's car.