Fear- that my adult son's depression since I separated from his (BPD/DPD) father is my fault.
It is okay to take care of yourself and put yourself first, not only is it okay it is essential.
Obligation- There must be something I can do to make him better.
The only people we truly control are ourselves.
Guilt- if I had just stayed in the abusive marriage, and continued pretending that all was ok, then he'd be fine.
An abusive marriage is no good for anyone...he would not be fine, he and you and everyone in your family would be living in dysfunction.
You have made healthy choices not only for you but for everyone in your family...you are a catalyst for change. Your son is uncomfortable with that change. As much as you want to fix him, his feelings etc. Your job is to feel uncomfortable letting him feel uncomfortable as he works through this himself.
On top of this, my married boys refuse to tell their kids ages 3, 4 and 6 that their grandparents are legally separated. They are convinced that this will destroy them and breed seeds of fear that their own parents could separate.
Your son's are projecting their own fears/or twisted ideas onto their kids here. I doubt it makes any difference to your Grandkids if you are separated or not, at their age they likely only care about seeing you and their grandfather. Married/Separated/Divorced you are still their Grandmother that's all they know.
I'm sorry about Thanksgiving their behavior is hurtful and mean.

Panda39