Is it normal that my cousin acts this way?

My cousin and I have always been close. He is a year older than me. When we were little we were inseparable. We are more like brother and sister than cousins. When I was little I use to have a crush on him. I got older and realized that it was illegal and got over it. Then he moved to another neighbor hood and we went to different schools. We still were close but we didn't hang out every day. Once when I was 8 and he was 9 we were swimming in the pool and he randomly asked me with a really weird smile if I would live in the playboy mansion, I didn't know what the playboy mansion was, but I heard the word mansion, and who doesn't want to live in a mansion, so I said yes. When he turned 16 and I was 15 he would drive to my house so we could hang out. When we would hang out he would act weird. He would what I thought was flirty but I brushed it of as me over thinking it because he's my cousin. A year passed by and now he would ask me what I liked sexually. He would say do you like it raw? How big? Would you give a guy a bj? One time when we were talking he put his hand on my mid thigh slid it up high and squeezed it. I was frozen in shock and didn't say or do anything because I didn't know what to do. He never did it again. A couple months after that he asked his and my parents if he could marry me and what would happen if we had kids. They said no and laughed it off. We all thought he was joking, but looking back now I'm not so sure. Shortly after that he got a girlfriend. Even though he had a girlfriend he would still be flirty with me. He would ask how I look without a bra. Would my boobs sag a little because they are so big. We text a lot on snap chat, and he always goes over the top telling me how beautiful I am. Which I find sweet, but a little odd. When we are out together everyone always thinks we are a couple, but that's what people usually think when they see a girl and a guy alone together. Right? he always gets a huge smile and says people think we are a couple. My mom once has even told me that we act like we are a couple. My friends all asked if he was my boyfriend. His girlfriend and mom once heard him tell me how hot I was and questioned why would he say that to his cousin. He also sometimes calls me his girlfriends name when we are hanging out. But that could just be a coincidental name switch. Like my mom always calls me my brothers name. Is this normal? Am I reading too much into this? Thanks for reading and for your advice.