Dev,

Hold firm!!! Don't you dare to go Gumby-legged on us.

W's reaction is not surprising at all. She's pissed that she's being called out for her behavior so, in a snit, she says she's done. You've put her on notice.

So from here and on....focus on the kids when talking with W.

"We are not talking if you are still with OM. Anything you'd like to discuss about the kids? None? Well, ok. Bye"

You WON'T LOSE the kids. It is between you and Mrs. Dev.

Don't worry about her behavior and reactions...it is all on her.