How do you talk to the in-laws?

[cw68]

My MIL is completely supportive of my H and his actions. Two weeks after we separated, she sent me a family cookbook that she had made with family recipes and little stories to accompany them. It came with a post-it that told me it was for me and the kids since I had requested family recipes a year ago. It's really neat and I showed it to my husband. He replied, "Yeah, I know. Mom sent me one too." So 14 days into our separation, she's already divided us up. She's also sent me an email that tells me that no one can promise that they'll feel a certain way forever, that no one should stay in a miserable relationship and that our first priority is to make ourselves happy. She dismissed my husband's EA because they didn't get physical and it's his right to have a friendship with whomever he pleases. She said not to worry about the kids because they are resilient, conveniently omitting my H's issues and her youngest son's drug problems, multiple felonies and the like. Though her oldest is very strong and steady!

Must note here that she's had three kids with three fathers, without long-term relationships with any of them (2 years being the longest relationship she's had and she's over 60). What stinks, too, is that she is a miserable, lonely old woman and IMO she's supporting my H to justify some of her choices.