am i in the wrong?

hi, i’m 17. this guy that i love recently left me because i didn’t choose him over my best friend. for context, ive been best friends with her for 7 years, and ive been involved with him for about 8 months. because of some rumors about her from his best friend, he believes she is a terrible person. but i don’t think it’s true knowing both of them. (i’ve been friends with his best friend longer than he has). i also “dated” my best friend when we were 12 but it was only like 2 weeks worth. but my ex friend leaked a screenshot saying i also liked her at 14 tho i don’t remember that. this is the main reason he wants me to choose. is it wrong im friends with an “ex?” even though it was so long ago? i broke up with him for her but we kept talking and now he’s asking me to choose cus i broke a promise not to hang out with her. which i made because i was begging him to stay. i don’t know what im doing at this point and he says i have until tomorrow night to give him an answer before he blocks me. j love him and i can’t stand the thought of him being with someone else or blocking me but he won’t move on from a past where i didn’t even know him so now i have to choose. i didn’t mean to hurt him and make him feel like i didnt love him, but i think he’s given up on me. what do i do?