how to deal with a cheater?

[gammazetagrl]

what would u guys do if the person you're dating (even just for a couple months) cheated on you? worse, actually he NEVER stopped dating his ex, so basically he cheated on her with YOU...which is in my case. Im sick of crying over guys that aren't worth it and really, I don't feel like crying anyway but I was just wondering what to do with him. He doesn't know that I know, neither does the other girl know there's two of "us" . Let's just say i heard it from the source itself that he's two timing...he told a mutual friend (which is really stupid in his part coz he should know itll get back to me) that he's dating me and this girl at the same time...but anyway it's supposed to be a secret between them two guys and theyre good friends and if i told my bf that i know coz our friend told me, i dont want it to ruin their friendship though...so is ther anyway to deal with this without bringing their friendship on the line?

My sister said make him suffer in the way like, make him jealous or act like distant from him because most likely he will be the one who'll come running (i wont take him back of course)....and even have him around still to get something out of it (gifts, dinners, etc--basically it's stupid of him because he's the one spending money, not me)and then dump him...so what do u guys think?