Am I being a rebound girl?

I have a big problem…..i liked this new guy at my school for a while, but unfortunatly i hide my feelings or mask them with other feelings..but anyway so i liked him for a while and i wanted to talk to him cause he seemed friendly..but them it turned out that he asked out my like best friend..i was really hurt…and then after that happened weird things happened..he was friendly i went to a party with friends and he was there..but without his g/f..well it was really cold outside and we were bored so we all played hide and seek..but i was fixing to pass out from the cold cause i didnt bring a jacket i didnt tell nobody i waz cold…but before i almost passed out he ran up to me in my hiding spot and held me in his arms and held my hands..it was romantic..but he is still goin out with someone else…..and then a year later we were friends, but they were still goin out at another party we started talkin and it turns out that he liked me and i still liked him since a year and a half ago and one thing led to another and we kissed and hugged, but now he has cheeted on my best friend with her best friend!! and he said if he breaks up with him that he would ask me out, but i dont want him after he said that because i still come after her and i dont want to be a rebound girl…..i dont know what to say to him???