Okay this is partly a vent, but also a 'what the hell do I do next'? question. 
My SIL is single, and childless and doesn't have any close friends. Last year she decided to buy a retriever puppy which as you can imagine, means the world to her. She brought it with her to stay over last Christmas. It was about 6 months old when it came and understandably, very puppy like, but my SIL imposed all these rules on us, in our own house about what we could and couldn't do - because of the puppy. We had to talk quietly, kids mustn't run, nobody was allowed to eat chocolate in case the dog got it, toys must be off the floor, we weren't allowed to sit on the floor because we must remain 'above the dog - all this at Christmas. She also wanted to sleep in the living room on the sofa with the dog because the dog doesn't 'do' stairs and when the kids came in a 6am to open presents she put the blanket over her head and asked when we would be finished.
Now the dog is twice the size and if you sit down on the couch, he sticks his nose in your face, and as she doesn't put him in his bed or wherever while we eat dinner he breathes on you while you're eating. He's always under foot, always restless and bored - poor thing - and he has a very loud and unpredictable bark. So this year, I said, if the dog comes to Christmas, it has to stay in the hall, knowing the would mean she would not stay the night - and I think that's best too - the dog doesn't want to be here and we don't want him here. The feeling is mutual. It's only her who wants to bring him. But this has unleashed a huge problem. We've had calls from relatives, 'why isn't SIL allowed to come to Christmas?' We confirm she is, but the dog has to stay in the hall. We say we're going dog free due to hair and mess etc (the easy answer) .… 'but your neighbour was allowed in with his dog!' And he was and the reason is simple, when his (smaller) dog comes over, he has a fuss and then sleeps in the corner. He's no trouble.
So yes, the issue is two fold, it's about being made uncomfortable by the dog AND about her ordering us around in our own home. The kids are also not huge fans of the dog as they are both under four and have cried at his barking.
But SIL has made such a big deal out of this that my husband wants me to just 'get over it' but he's not the one hostessing and cooking and 'doing' Christmas.
So the idea of her not coming for Christmas was - well - okay with me. But now she says, she is coming to Christmas, without he dog, and that she won't speak to me while she's here. 'Okay, then I won't make her any Christmas dinner'. was my reply but my husband's shoulders went up to his ears. He is so stressed now, I don't want to make it worst. Any advice?