I think your response about the 50/50 parenting time is great. I dont think you should give her the time of day concerning her latest spew-mail. I do think your W is one of those that actually is addicted to getting mad.
Cleaning up all of the clutter my W has created around the house is indeed a nightmare. I lived in the house 5 years before I got married and always kept it neat. I will get it back there and I am sure you will too. Just have patience and dont try to do it all at once. It is tough not letting the mess get to you.
