Demanding that she cut off all contact with your friend is a bit over the top. OP, be reasonable...I agree with >>20. Saying that there are strict rules you have made that she must follow or be smited by whatever higher force you hold holy is overwhelming. ('o') be careful not to scare her to death or whatnot. At any rate, I think that >>16 was probably pissed that you were all "Gahh!" and stuff in >>13 but I kinda think it's good that you got to vent.
But honestly, do you really NOT care about her and everything? Do your really want to give her up? Cause I think you do. You're just insanely fustrated. Patch things up and come to a compromise before running off and doing something rash again. Because I really think that you do care about your girlfriend. Not all relationships are going to be sunshine and lollipops. Besides, talking to another man on the phone for hours, considering he is your best friend...is your friend likely to snatch her from under your nose? Maybe she needs someone to talk to about how to handle a relationship with you, since she doesn't know what she does is upsetting you so much.