I totally understand. I spent years suffering this kind of abuse from my DIL forever turning a blind eye, forever doing things to make her feel safe and appreciated.
I remember once after she had suffered a miscarriage, just before her wedding I sent her a box of chocolates and card ...and she rang me up and asked me why I did that.
I've found out since that she has a genetic disease (MD1) which all my grandchildren (her children) have sadly also inherited. It can affect social intelligence etc as well as muscles so I now see a lot of it was perhaps caused by that. But her possessiveness and paranoia and personal attacks...its so hard to take.
Her children are very sweet and she is a very devoted mother. She's been my DIL for 14 years now...it hasn't got better or worse...and I mercifully have stopped feeling so raw and upset by it.
I remember once after arranging over three days to drive over to see them one Sunday afternoon, involving motorway, full of lorries and ever changing lanes so very long stressful drive for me, but I felt I had to make the effort. And when I arrived on time they weren't in. I remember bursting out crying on their doorstep (which shocked me) I rang them and they came back about half an hour later. She said in future I should have rung on the journey as she does me (she doesn't drive, she's a passenger...I was alone and I didn't have in car phone connection I was concentrating on getting there on time.)
She is an only child, adores her father, and is a bit scathing of her mother. I tried to make friends with her mother but her father got back to me and suggested all messages went through him as he said her eyesight was bad. I just don't go there now.
I wish my son could visit without her but that wont happen although she always turns up at mine looking fed up and furious. She's convinced my son has a very close relationship with me which is actually no longer true in the way she fears now he is a grown up. He's doing his best. I've never said anything negative about her to him. She's never allowed me any time with my, only, grandchildren alone. (that upsets me to write it)
Its a most unexpected nightmare. I've always been a woman's woman and the last thing I expected. I always hoped I'd gain a daughter.
So I have full sympathy. and give you a big hug. Ive noticed on mumsnet you see a lot of MIL-hate and advice for NC (no contact). Its very sad.