Why is my ex like this?

We have not been together for over a year, so the reason why he still acts like this is beyond me. We hangout and are friends but sometimes its like its really hard to forget that we are actually just friends and nothing else. He doesnt like guys in my life....he thinks they all just want sex from me and he doesnt want me to get hurt or to end up with some loser. I dont think he would think anyone is good enough for me, he would think they are all bad. He is really protective of me, and just like he is always checking in on me. He calls me often and whenever he is town he wants to hangout. And when Im in his town he always wants to see me and hangout. I like to hangout with him, but he can be a real asshole at times. Even though I know that though, I still love him and there are moments when we can just talk and its like everything is ok. We can be honest with eachother. Thats what I like about us, we can just be ourselves. He always comments on what im wearing and sais I should put on a sweatshirt or something, because I have big boobs and its like he doesnt want anyone else to see me and that he doesnt want guys to check me out. He brings up sexual stuff that we did quite a bit on the phone, and then sometimes he will be like ewww gross you naked when I say I just got out of the shower. When I was with him a few days ago we were kind of like pretend fighting and he acted like he was going to kick my butt but we were just kidding. He like grabbed my stomach kind of and let me beat him up haha. Then he will give me long hugs sometimes......not always but sometimes. I just dont get it anymore. Its just confusing. My mom, my sister, my friends think its confusing too. Btw....my ex is gay. Which doesnt make any since because he goes back in forth from him being gay to him being bi only for me. lol.. ya I dont get it. I dont even think knows.....