She's just spinning spinning spinning. And it's possible that the reason is (although she doesn't know it) that she's just incredibly jealous you're engaged. Stupid, I know - but somehow many of the WAss seem to always think we'll be there for them if they change their minds.
She's probably not conscious of this.
I agree with the advice to stop picking up the phone. Let her calls go to voice mail, then send text or email replies (carefully worded, always). Keep copies of all her responses. Don't talk to her without a third party in the room. A counselor was a good suggestion. She probably won't take you up on it.
And if she's REALLY worried about the disruption to the kids, tell her you'd be happy to keep them every week and let her have them on weekends.
