I think your XW MLC is ending and she is trying to tell you that she wants to come back. It's time to turn on acceptance and have her back in your life, don't make her life even more complicated. At the end of the day it's in the best interest of the children to have their mother back. Don't criticize her, don't make her feel guilty, don't turn her away. Just act as if nothing happened and get her back in your life, just tell her to come over for dinner and bring a bottle of wine, keep it simple. Hugs.
