Well you are not alone. This has been a sore subject on this site for years now.
I tried for years to get my husband and his mother to spend time together, I think I am still wiping the spit off my face. We went to CA to visit quite often when we first got married. I would always call in advance to arrange this, letting her know when we planned to be there and when we planned to leave and what our plans were. I would ask if this will work for her and she would just say she couldn't wait for us to get there. As it turned out, she never changed her schedule once for us. She would drag us all over town so she could run her errands and then we were available to have lunch with her when she was ready. My husband and I would just look at each other while holding our comments.
Tomorrow, she and her husband will be cutting through Vegas and plan to stop by. She only stays for 45 minutes and I mean 45 minutes! We had planned to go to the county fair about a 45 minute drive from our home. She never asks what our plans are, just that she will be here. Well, my husband said the fair comes once a year and she passes through here about 4 times a year, she can meat us at the fair and park their RV there. Normally I would tell him it is not right, but I stopped trying about 4 years ago when our beautiful baby girl was born and was treated the same way.
I always thought respecting your MIL was part of the marriage, no matter what. As well, I was ignorant about the children thinking all grandparents would love to see their grandchildren even if in small doses. Forty-five minutes is hardly a dose, it is an insult. I just learned that my mother refused to go to my grandmothers house because she was treated poorly by my grandmother and my dads sister. She said she wasn't about to sit there and be a target. I had no idea.
The important thing, try to let your children form their own opinion. If possible, try not to let them see all of this, even if it means staying away.
To think, I broke up with a guy I dated before my husband just because the way the family treated me. It is amazing they are allowed so much control.