To room 19

This is another short story I read recently and I summarize it as follows:
When you start reading it, you come accross a young, wealthy and well established couple, who own a big house and have four children. Apparently, everything should be all right, but the wife feels all alone and desperate. She had to do without her professional life and that - among other reasons - makes her feel down.

As the author goes deeper into the main character's psychological status, we discover that she really needs to have her own private time and space. Eventually, she decides to rent a room in a dingy hotel in London, where she spends a few hours each day.
Whatever happens next, you have to read by yourself.
The author of the story is Doris Lessing. She got the Nobel Prize not long ago.