My girlfriend cheated on me with myself?

ok i ask a question on yahoo long story short they told me to test my girlfriend so i created a fake facebook name him raymond lol i added my girlfriend long story short she gave raymond her number raymond ask can i see you she said when? she told raymond she broke up with her boyfriend cause he cheated WTH lol so few min later she text the real me on my phone in ask have you ever had sex with another girl while we was together like wtf what made her ask me that ? then i said heck no .why did you. she said no i ask her did she ever cheat or give another guy her number she said no only your brother idc about her telling my brother her number because he dates her sister so she text raymond give me your number in maybe we can hook up WTF???? then we talk again i ask her did she ever cheat she said no i think cheating is stupid a waste of time i only cheated on 1 guy in that was an experiment to see how it felt. so should i brake up with her cause she lied to me about cheating unless she thinks thats not cheating. should i continue to talk to her with raymond or kill raymond lol