NC is key to getting the fog to break. Affair fog is a powerful drug. You have to be willing to lose the relationship to save it. Remember not to get into too heated of an argument with someone in an affair. They're not themselves. Keep yourself very calm and under control. Explain that you love her and are willing to meet her half way to mending your R but that you will not tolerate an open marriage and any affairs on her part will lead straight to divorce (not a fan of separation, that's not serious enough to snap them out of it in my opinion.).