So glad Sandi stepped in, she's put it in a nutshell.
What concerns me is what you've said about your D's. Have they picked up on how your W treats you and are now following suit? I think you need to make a stand against the unreasonable behaviour of your W (in a calm, measured way) to show your children it's not on to treat anyone that way.
As to Thanksgiving...make dinner, enjoy the day WITH your children. I personally wouldn't invite the in-laws if you're going to be uncomfortable, but if you enjoy their company invite them, STAY and enjoy the day. W can lump it or leave it.
Me 50 H 48 S 23 S 21 D 19 Together 31 years Married 25 years Separated April 2009 Reconciled 2010 Separated September 2017