So I've been sleeping with this guy for about 7 months and he told me the other week he slept with this other girl. Mind you all three of us live in different cities. I have stalked her Facebook, I can tell that she really likes him and she has no idea that he's sleeping with me. Should I sent her a private message and tell her that he's sleeping with me just so she knows and hope she doesn't tell him? Or should I just leave it. It's annoying because she comments on every single one of his photos being like all in love. It's actually getting ridiculous, she thinks she's the only one but little does she know.. The other night he sent me messages telling me how much he missed me then he slept with her the same night. What should I do?