My girlfriend cheated on me twice.. what should i do?

Dude i don't wanna say once a cheater aways a cheater but in this situation you need to be really careful because girls are good lairs they can make you feel like you are the only one in her life then you turn around and she starts blowin your friend off..you need to make sure this girl if really in it like you are because its nothin worst then lovin someone more then they love you then they finally get tired of playin the love show so they dump you and you are left with all the pain while she goes out and parties hardy with her friend that same week and ends up blowin some guy by the bar if i where u i would end before it happens to you