So how much energy should you invest in contemplating it?
Her "therapist" often works with her spouse, they both come from divorces and have a mixed family. When they team up, "therapist"'s H sees the H, while W sees the female. They/we then come together and work on an action plan.
This does not feel right to me. A more positive outcome is conceivable, but I think this is a trap. I've said flatly that I will not participate in a collegial divorce action plan. Sorry if that is invalidating, but that's my boundary.
If W is going to drive this potential train wreck, she can own it and the consequences without my buy-in. And, to your point, my involvement in that particular process is what I can control.
Part of me is tempted to meet with the "therapist"'s H and tell him that I won't be manipulated into anything, and "therapist" needs to get off her a$$ and do therapy rather than enabling my W.