BTW what’s your relationship like with your ex MIL? If it was good, and if she’s a reasonable person, you might try communicating with her directly on the Xmas thing, as ex is likely either misinforming her or using her as an excuse. If she doesn’t know about his cheating on you btw, you should tell her if you think it will put her more in your corner. At the same time though, blood is thicker than water. Don’t count on her, but you explaining to her how equitable the Xmas plan is might reassure her. ( Your ex might be painting you as some horrible person who is going to keep their grandchild from them).
