When we decided to move in with David's mother after we were forced out of our apartment, I declared from the first instant that I would be taking over the finished basement room. As it stood, it was just a storage space for books, furniture, and a lifetime's worth of National Geographic Magazines. David said I was welcome to it, but that he did not intend to spend any time down there, as he had never enjoyed being there as a kid.
It took a while for me to get everything organized, including the acquisition of a reading chair and the expulsion of a lot of stuff that was going to Belleville, but it really became my own space this summer. I have my desk and my laptop, plus bonus screen for when I work from home. I have my big TV and cable. I have my reading chair and all the books I decided to unpack (which was mostly the ones I am very attached to or haven't read yet). I have the bar cart. I have snacks. I have room to do yoga. I even have a bathroom.
I always took Virginia Woolf's essay to be metaphorical in a certain sense, but I have a room of my own now and it is GLORIOUS. With David gone during the week, I have dinner and make small talk with my mother-in-law, and then I change into my soft clothes and head into my cave. Everything I need is down here, so I can work, watch TV, read, or nap as I like. I particularly love weekend days in the winter where I can just come down and loll about without feeling guilty about enjoying being outside. If I bring snacks I don't have to leave for hours.
The most interesting thing is that, despite all David's protestations that he'd never come down, he comes down all the time when he's home. Since my MIL never comes in, it then becomes our sanctuary to have a quiet conversation or watch a movie or just sit quietly on our phones with the cats.
My Sian Cave is something I will fight to keep even when we don't live with my MIL (someday), especially, I think, when we have kids (eventually). I don't need a craft room or games room, but I do need a room where Momma can be herself no matter what.