I [F17] have a weird and confusing relationship with my best friend/neighbor [M18]. Need advice on how to approach the situation.

For about a year, I was seeing/having sex with my 18 year old neighbor. Nothing was ever really official but we were basically together but after about a year of us hanging out and having sex, we both decided not to take it any further and to just stay friends even though I wanted more. We continued to have sex and I eventually let him know I wanted more. When I told him that, he told me, "this isn't supposed to be that," and didn't talk to me for three months. Then he started texting me again like nothing ever happened. We talked a little bit about it when he started talking to me again and I told him that those feelings were still there but I had accepted that all I would ever be was a friend and I didn't expect anything to happen. Now, after about 6 months, we're best friends and we hang out all the time and talk constantly. About a month ago, he was at a party in another state when he found out that I was dating some other guy. I posted a picture of the guy I was seeing on Instagram and me neighbor commented on it saying "Really? This is the kid?" and making fun of him and then he texted me and he was getting kind of hostile about the situation. The guy I was seeing also texted me and asked me about it and then he broke things off because he didn't want to deal with my neighbor pulling that stuff. When I got mad at my neighbor, he kept saying he was sorry and then he told me "I would be with you if I could." That doesn't make much sense to me. He said we wouldn't work because my mom doesn't like him because he has a daughter. So, he said that, and I got pissed. I just thought it was very unfair of him to say that after I had accepted that we would never be together. When he said that, he put me right back at step one. I had to accept it all over again. It seems to be harder for me to accept it now that he's said that. He also has a girlfriend. But, he asks me at least once a week if he can come over to cuddle. I tell him no, and to call his girlfriend instead every time he asks but he always tells me no cause he'd rather cuddle with me instead of her. I respect his girlfriend too much to do that to her. I don't really know what to do about it. We both act like it was never said and we didn't talk about it any after that night. My mom told me to confront him about it and basically tell him he needs to make up his mind but then there's part of me that doesn't want to. If any of you have any advice that would be awesome because I'm obviously stuck. I also apologize if I confused some of you. tl;dr: Had a non-official relationship/friends with benefits type thing with my neighbor who is now my best friend who can't make up his mind.