Yes, I've dealt with a bit of that. I ignore it, and make it clear that's not going to be the case by cutting off nearly all communication with my W. In divorce mediation I bring up the fact that in the event of my death my life insurance and social security will need to be split up between my kids with her, along with my then current wife, and possibly (step)kids with her. I said I will arrange for a trust fund for the kids, managed by my father, not her. She asked "What happens if your father dies?" I reply "Then it goes to my brother to manage." I told her I wanted to arrange the custody schedule so that the kids' transitions are mostly handled via the school bus, so we don't have to see each other. When she asks about my social life, I give her nothing, and I NEVER ask about hers. I think she gets it.
The fact that you're even having these conversations with your estranged W says that you haven't established good boundaries. You can't stop her if she wants to leave you and end your marriage, but she doesn't get to dictate how much you'll allow her to remain in your life. You do. Don't let her use the kids as leverage. If you establish clear boundaries, the kids will get it.
