If you know, and she KNOWS that you know, then I believe that is where her "Why aren't you fighting for me?" comment is coming from.
She is losing respect for you, because you are tolerating her affair, in my opinion. And since women tie their feelings of LOVE very closely with their feelings of RESPECT for a man, I believe she is rapidly losing love for you as well.
Combine all that with the physiological fact that she is addicted to her OM (just google "PEA brain love lust addiction" and do some basic research on the endorphines that wash over someone's brain when they are in an affair), and you're in quite the pickle.
