How do we know that the woman spends a lot of time in the room?

From the text:

And I am alone a good deal just now. John is kept in town very often by serious cases, and Jennie is good and lets me alone when I want her to. So I walk a little in the garden or down that lovely lane, sit on the porch under the roses, and lie down up here a good deal.
I'm getting really fond of the room in spite of the wall-paper. Perhaps because of the wall-paper.
It dwells in my mind so!
I lie here on this great immovable bed--it is nailed down, I believe--and follow that pattern about by the hour.