So why would you want to live the rest of your life with a person who tells you up front that she will never be able to forgive? That means you will never be able to make a mistake! Life is too short to be spent on a selfish person such as she is! I can't believe somebody would be so stupid and self-centered to think it is okay for her to be unfaithful and for you to forgive but she doesn't think she should be required the same. Well, you can keep discussing & cussing about it or make up your mind to either kick her to the crub or live in misery the rest of your life, b/c that is exactly what you will do if you give in to her silly and immature, selfish ways. Of course.....there is always another way, but it would mean standing up to her and telling her you aren't interested in being M to somebody with such little character as her and turn around and leave.....and stay gone. I think after a while when she saw you weren't going to chase after her....she would look you up. This would take courage, and only you know if you have what it takes!
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!