WW is onboard with trying to save the M

[JGuy]

I'm not sure thinking about this as "setting limits" is a healthy term. You don't want to be thinking about this as restricting her ability to make choices. Instead, you're intent is protect yourself.

It's not: "You can't contact OM or else I'm leaving."
It's: "I wont be with you while you're contacting OM."

This choice is hers to make, not yours. So when you make that choice for her, it's not surprising that she gets "huffy".

I get it. In our talk last night, I definitely didn't present this with the intention of making the choice for her. I explicitly told her more than once that she is free to choose where she wants to go from here. She can continue pursuing the R with the OM if that's what she chooses. If she does, then to protect myself I will start taking steps to get a separation.

The truth, of course, is that I am nowhere near neutral and I do really hope that she chooses to end it once and for all with the OM. Even so, I think I'm doing a good job of letting go and not trying to manipulate or control her choice by using the threat of separation, but it seems like the rut of feeling controlled and manipulated is very deep in her psyche. That was one of the main patterns with how her mother always mistreated her. She seems to always react in that way and see my boundaries as controlling, even when I try to communicate in the detached way that Azzork suggests. Maybe I can do better... I don't know. The negative imprint of feeling manipulated seems to be so strong in her, that tragically, it is like a self-fulfilling prophecy and as long as she's engaged in that story, the only thing I can do is back away from the R.

Because I can see this pattern (and the MC has also called her on it) it is very tempting to try and point it out to her in the moment it is happening, in hopes that she will realize and snap out of it. However, I'm trying to avoid pursuing/fixing, and am worried that doing so will backfire. Therefore, I am left sitting on all these tragic feelings, seeing our R falling apart, feeling like I can see what will help, but having to remain hands off and let her learn on her own, even if that means our M fails. This is very difficult for me, given how badly I want to save our M!