Oh dear. I do sympathise. I have a very extrovert neighbour whose pet phrase when I turn down the third invitation in a week, is “I absolutely insist”. When I have the energy to stand firm with a “no” as opposed to “no thank you”, she becomes petulant. It is hard because I end up doing things that, while not unpleasant, are not what I’d choose or, what feels worse, I feel rude when she won’t take no for an answer,
Can you mitigate by arranging with the hotel to have a table for two at breakfast and tell the floor manager not to let the others change this. That way maybe you have a better chance of spending at least part of the day off on your own.
Better still of course, but requiring a lot of courage, would be to change the dates, especially if there is no extra cost. We can’t buy time, and I have found it easier to say no because of covid, enabling us to prioritise our own choices and not be second fiddle. Easy to write but not at all easy to do.
What was your husband’s reaction to the news? Does that give you wiggle room?