The narrator is a doctor who although probably filled with good intentions, comes off seeming domineering. He treats his wife almost like a little child. Right off the bat she mentions that "John laughs at me, of course, but one expects that in marriage."He is laughing at her silly ideas about the vacant house they've taken; she tries to blow it off by saying that's just what marriage is like. She is trying to obey and play the role of a "good wife"; already though, you sense a strain. She mentions that he doesn't believe she's sick, and forbids her to work. Personally, she disagrees, but supposes he is right, so she acquiesces. The tension makes her "unreasonably angry with John sometimes" which causes friction, so she takes "pains to control myself -- before him, at least". She says that "He is very careful and loving, and hardly lets me stir without special direction" which indicates that he likes to feel in control of her, like he is taking care of her, but might go overboard and be a bit manipulative and controlling.
All of these things point to a forced relationship that is outwardly polite, but inwardly strained and unhappy. In the end as the narrator slowly loses control of her mental state, we see that anger towards John come out as she locks him out of the room, refusing to let him in and help. That inward strain finally takes its toll, and the results are disturbing and unfortunate.