This is a gift

[IronWill]

Good for you - standing up for yourself, U. Backing off and letting her deal with her own issues is beginning to show it's effectiveness.

She has no intent of R'ing in MC. So I'm stopping it.

Good. Very glad to hear. You will feel much better. Less chances for BDs while she is going through this. You need to remove yourself as a "reason for all her problems", regardless of any outcome. The best way to do that is time and space.

I think her goal is managing a long separation while the kids are young so she can avoid going back to work as long as possible. She has never actually stated a goal. But it's clearly not to work on the MR.

Be careful mind-reading, here - it could be anything. Step out of "the why", you stop going because you don't want to go with someone who won't work on the MR. You have a boundary here, and you set it.