Mother-in-Law Dearest
Nobody’s supposed to have a good relationship with their in-laws, but the OP had a pretty disastrous one right from the get-go. There’s quite a lot to unpack in this story, but long story short, the OP, a bride on her honeymoon with her husband, had to share her honeymoon suite with her MIL.
She had no choice, really. See, the mom was paying for their honeymoon suite, and she had just gotten into a huge fight with her husband. Instead of packing up and taking a cab home, the MIL decided she’d bunk with her newlywed kids for the night. She almost wound up sleeping in the same bed with the groom had the OP not put her foot down.