Manipulative mother in law

How do you deal with a manipulative person? My mil is so manipulative it drives me insane. She is like a child and is passive aggressive when she doesn't get her way. She asks if a weekend works to see us and we say we aren't sure we'll have to check. And she says okay great see you then! Unless we say we absolutely can't make it, she hears what she wants to hear and bulldozes over us. Then when we change it to be something we are comfortable with, she's all "disappointed" and tries to guilt us into more. It's like we give an inch and she'll fight until she gets that mile. My husband has tried to talk to her but it's useless. I actually get a physical reaction when she pulls shit like this I have a knot in my stomach. She is toxic to be around and every time we talk with her this happens. Then she gets upset when we ignore her. I just don't know what to do anymore. If it were up to me I would cut her out. And my husband would like that too but at the same time it's his mom so he can't do it. The more I deal with her the more I really really really do not like her. Thanks for anyone who reads this and has advice!