Wait a minute, Kerry. There needs to be a VOTE before we actually acclaim FLTC's ex as the worst. I agree - she is HORRIBLE!!!! But many of us could write a book about similar stuff with our exes too.
The only answer is to let her spin out of control and just step back and stay out of the mess. Anything that is harmful to the children or not in keeping with the agreement is to be dealt with by your lawyer and hers. When I finally learned this (took about 6 years), I stopped reacting to everything and refused to give into his demands and uncontrollably bad behaviour. Now I just pretend he is someone I once knew and take care of my own world and the needs of my children with no thought of him AT ALL!