I pretty much always think people have a husband problem, not a mil problem.
MIL can only get away with shitty behaviour if their son's allow them to. People often focus on their mil's behaviour because it is easier to hate her than put the blame where it often lies, the son. Of course many mil's can be nasty and cruel, but they can only get away with it if their son allows it to go on. That doesn't mean their mil's behaviour is ok, and they aren't responsible for their shitty behaviour, they are, but the solution is simple, if not easy. If the son sets boundaries, puts his wife first and makes it clear he won't tolerate that behaviour then it can't go on. Of course I am talking about the real toxic mil's, not just the slightly annoying ones that aren't really doing much harm.
I had a massive problem with my mil, and I liked to hate her for it because it kind of hurt knowing my husband didn't have the guts to actually do something. He did eventually, when I changed my focus from what mil was doing to what my husband wasn't doing. It was just too late.
I was a great dil. I invited mil to stay over when dd was born because I knew she wanted to be a massive part of it. We had her over for one afternoon a week and went to hers for dinner once a week. She had dd on her own every other week while we went out. Every Xmas we made sure we spent at least some of xmas day with her. She could not have been more involved and welcomed into our every day lives. I probably saw my side of the family less because I knew mil was struggling with letting her son go and I wanted a good relationship with her. I shot myself in the foot though, because she ended up thinking she had the right to involve herself in every parenting decision and every aspect of our lives really. It all got rather nasty, especially when she accused me of tricking dh into another pregnancy by taking my IUD out, having sex, and then putting it back in
. It's a long and boring story with much much more to it, but my trying to be this perfect dil seriously backfired. But really, the problem laid with my husband who did fuck all about it for so many years.
TL:DR