I do see her point about the phone calls happening while you were together, cheating can also be emotional cheating, which to many if not most women is more painful than the other kind of cheating. Men and women tend to differ on that point. However, it sounds like the relationships problems run long and deep and the cheating is not the only issue by a long shot. At best she has some big emotional problems and an inability to communicate in a respectful way, at worst she's being mean and callous. You may need to face the fact that this relationship is not salvageable and that it's time to move on, this time permanently.