thoroughly confused!

prom was last week and i was supposed to go with the obvious person, but then there were some complications. i had told him that i might not take him anymore and then like maybe 4 days later i asked him to go with me again. he said he would love to go with me but that he might be busy. i just figured he had to work or something. a couple days later i found out at school via the grape vine that he was actually taking this other girl, the same girl he left me for. i was so angry and i felt so betrayed. i confronted him about it and he told me that he wasn't going to tell me and just try to avoid me at prom thinking that maybe i wouldn't find out. to me this sounded like the dumbest thing ever but apparently he doesn't think very well even though he dwells on issues and thinks way too much into them. i told him that if he was going to prom with anyone it should be me and that i didn't know if we could be friends anymore. the only thing is that i don't know if i was out of line. i know we have a lot of history and there was no doubt that i was definitely hurt but we are not going out and i technically do not have claim on him. i just do not know if this is a big enough deal to end our friendship. i'm just so confused but everyone else thinks that i should never talk to him again but i don't know if i can do that.