I was in a similar situation with my mother-in-law. She used to live here in Ohio, but she moved years ago to Florida. She wanted us to move there too, but we opted to stay here because that's where our jobs are. I have worked at the same place for 22 years. So, she blamed ME on the reason we wouldn't move down there, even though it was actually mostly my husband who didn't want to. He actually liked the distance between them because she is very controlling and devious.
Several years ago, she started to cause trouble at Christmas time. She was coming to Ohio to stay with her daughter, but she was trying to control all our plans. She ORDERED me to take off work, even though I had already used all my vacation time for the year. Then, because I wouldn't follow her orders
she emailed my sis-in-law and said some pretty bad things about me, and made up alot of stuff. What she didn't count on was my sis-in-law showing me the email. She would also bad-mouth me to my own children.
I made a decision. I knew that I could NOT stand being around this woman anymore. So, I told her and I told my husband that I would never interfere in their relationship. They can see each other and talk to each other as much as they want, and I don't care. BUT, I refuse to have anything to do with her. I also said she could see my kids anytime she wanted. So, my husband visits her when she is in town, and he talks to her occasionally on the phone or via email. My kids aren't that crazy about seeing her because of how she bad-mouthed me. They're adults now, so they can make up they're own minds. I never talk to her or never have to listen to her very annoying LOUD voice anymore, and I never have to see her. It has worked well for us.