The boundries are tough. Between the lies, their sense of entitlement, and their self serving fantasies, it makes it hard to know what to do. All of this has been a lesson for me about what truly is within my ability to control, and what is outside of my control.
Do your best to give your kids the safety and stability they need when they are with you. Help them deal with the chaos and uncertainty they find when they are with their dad. You can't control his actions. Even if all you can do is give them a safe place to rest, you are giving your kids an invaluable gift.
