I would have suggested to go to her home for the holidays and just put this issue on the back burner and just talk about the kids and neutral stuff...but the reason I didn't was because this man was abusive to your mom, that would almost impossible to pretend this didn't happen...
Can you just make a nice dinner for you and your DH and your mom and just enjoy the holiday together....put on some nice music and make cookies together....your DH would probably love the quiet....just try and make the best of the situation that ...I hope your holiday works our for you
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