But it I want to avoid a D at some point I assume I'll need to resume friendly, normal interactions, and allow her to see the positives she is missing?
R,
This is all a mindset you have to first establish before you will see any changes in your situation. You have to get to a point where you say this is BS! Why am I fuching waiting around as plan B while my W sleeps around to see if maybe she will get tired of it and come back to me.
If you have dinner with her, go climbing with her you are going to end up becoming her gay male girlfriend. Next thing you know she will start talking to you about then men she is seeing.
When someone changes the terms of a relationship that you don't agree with you walk away and never look back and she gets the gift of missing you. That is strength my friend.