My relationship is being destroyed, what can I do?

My daughter in law is big on finding one word out of everything I say and manipulating and twisting it and twisting until no matter what I do and say fits what she wants everyone to think of me. I have not done anything wrong. She says she wants me around, but then... That's right it happens again. I've never met anyone ever in my life who is so insecure and controlling And manipulating. I have three grandkids and 1 son, But she is killing the loving relationship we have had. My son is 38, grandson 8, G daughters, 12 and 17, those two I raised. They are by ex daughter in law. This behavior of new, not so new anymore daughter in law has been going on for 9 years. My heart is breaking in half. Can't deal with her anymore, but that means putting kids through more. SHE USES THE KIDS and my Son. I see guilt in his eyes and only coldness in hers. HE can not stand up for what is moral. He use too, but I think he's brainwashed, The kids are hurting.They have to do what she says or eVeryThing she has ever given to them will be taken away. AnD they would be scrubbing floors instead! I don't know which way to gO anymoRe. So immoral and SaD.