Uh, she really sees this as a game. Why in the world, if she wanted to be with you and only you would she want you to sleep with someone else? I think you're making yourself too available and open to her. Take it down a notch.
Can you go no contact for a while so she can at least start to miss you and realize what she's losing? Right now she has you right where she wants you and she KNOWS it.
Me: 32 H: 32 M 9 yrs #1 D7 #2 S5 #3 D2 Bomb 8/12/11 H moved out 8/14/11 PA started w/H & OW in 1/12 - found out 3/24/12 Got my own place 8/25/12 H & OW move in together 9/15/12 Still married.