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talk to the guy you like. see what he thinks about you. see if he believes the rumors your ex started. talk to him about it and get his opinion. let him know that you're not a whore and that you want a sturdy relationship. good luck!

Everyone tends to do those kind of things when they are young.
People in middle school/high school usually talk s**t about their exes.
Its fairly normal.
I'd be lying if I said I never said rude things about my exes.
To be honest, its part of growing up and relationships.
You just have to not let it get to you and realize that the people who love/like you will stick with you and be on your side no matter what.
A guy who likes you for who you are (not the rumor) is the guy you should be with.
If this one guy has heard the rumor and he only wants to get with you cuz he heard you're easy, he's not worth your time.
If and when you guys actually start "dating" or whatever just make sure you get that point across that your ex made up a rumor and if thats all hes interested in that you arent that girl.
You really just need to talk to the boy whom you like about it.
Telling your ex to stop isnt going to do anything...boys are immature.

Life goes on, a year from now I promise you wont even remember the rumor.