Why did the writer not provide us with detailed information about the character and situations?
The strength of this story lies in our being able to infer from the action of the story what this marriage is like. Would more details about the husband or wife give us any greater a sense of the dynamics of the marriage? Probably not. When this story was written, women had little power in their marriages and were often trapped like birds in gilded cages. Sometimes this is still the case. So a reader of this story is free to identify with the woman, bringing the reader's own experiences to the story, enhancing its impact. Many details about the characters might tend to make this a story about just one particular marriage, rather than making it a story with great universal appeal.