Hi, D&C. Just wanted to chime in here and say that I completely agree with Puppy and Grumpyeby, and I, too, don't believe Puppy was implying that you hand down ultimatums. The only way it will come off to your W that way is if you don't choose your words carefully. Use "I" statements rather than "You" statements. Explain your boundaries to her, and if she perceives them as ultimatums/demands, then make sure she understands that they aren't at all. They are merely your personal limits/dealbreakers/boundaries. They are what you will or will not tolerate in your R. The choice is hers as to whether or not she will respect them.
So ask yourself: What am I willing to tolerate in my M? What am I not?
Can you put up with the cake-eating and look the other way? If yes, then stop focusing on W, OM, and the A. Do what you need to do for YOURSELF. Detach, GAL, and be nothing more than a friend to your W, and try not to be so available to her.
Getting over a painful experience is much like crossing monkey bars. You have to let go at some point in order to move forward. ~ Joseph Campbell