Question:Why does my ex think he can use me like this?

My neighbor and I used to date about a year ago. I did not have sex with him. Hes 17 and Im 14 now. He used to me and at the time I was 13 and I didnt know anything. I let this boy use me for a year. Today was the first time I saw him in three months and we didnt even barely talk but then after wards he wanted to go swimming with me and I kept saying no but then he was like then we can go swimming this week. Then he went home and then about 30 minutes he came out and I wasnt paying attention and he was out there. He wanted my aim so I gave it to him. He aimed me as soon as I got on saying hey are you alone and I wasnt but I just said yes unaware of what he wanted he wanted to Cyb with me. I told him I dont do that kind of stuff but he just kept on and on finally I told him I had to go. This boy uses me so much and Im sick of being used. What do I need to do?