Let go of her, let her be with the OM. Agree with her on the separation, tell her she needs to move out soon, within the next few weeks, you guys will arrange joint custody and you will start enjoying your single life as well.
My Plan is to reinforce her move out date of Jan. 11th.
I told her this very morning when she called it's is strange you mentioned something similar Robx-
I told her that she doesn't need to make her returning one of the kids from an activity in the evening into an excuse to vacuum bedroom and stay till they go to bed. We need to get the schedule set and each have the kids accordingly.
M43 W43 D11 S7 M18 T20 WAW is back & trying (no she was lying) Close to callin' it busted but.... watching Whatever the outcome - It was a choice.