I think my best friends ex likes me.

okay, so in order to know the background of this, you must know that my best friend since I can't even remember when had this guy that she was sort of dating since she was about 13-15. during this time, me and said guy became pretty good friends (like really comfortable like just throwing harmless burns and insults and just always goofing around). Anyways, they've always had problems Because I guess they just weren't compatible together. The only time they wouldn't be fighting is when they were kissing or going down on one another. they don't talk AT ALL now. she doesn't even want to bring him up. it's kinda sad, really. anyway so this year in school he's in my English class and even though they don't talk anymore, him and I are both still close friends. or so I thought. throughout the year he's been really flirty with me and I talked to my friend about it and she said he definitely likes me and it's okay with her but I don't even know if I like him. he's a nice guy and all, but I don't wanna but any barriers between me and my best friend. I just need to know what you guys think of this whole situation. I need to talk to some other gals who've been through this and can tell me their stories and spread a sista with some of their wisdom😫😫🙌❤