>>25561403
Marriage

>>25561403
Subtextual reasons.

>>25561403
Why did Stoner rape his wife?

>>25561403
Are we supposed to have Edith Hate General now?

Socio-economic factors

>>25561403
The novel repeatedly makes the point that we're not given to understand the inner workings of another person's mind. Everyone save Stoner is, at best, slightly transparent, or otherwise totally opaque.
You don't fully comprehend why his daughter starts drinking or why that crippled academic has such a chip on his shoulder or why the other academic is spiritually destroyed by the breaking out of another war.
You have some hints to draw from, but only those that can be woven into an existing stereotype or cultural archetype which, during Stoner's relationship with the grad student, the book cautions against.

>He had a glimpse of a figure that flitted through smoking-room anecdotes, and through the pages of cheap fiction--a pitiable fellow going into his middle age, misunderstood by his wife, seeking to renew his youth, taking up with a girl years younger than himself, awkwardly and apishly reaching for the youth he could not have, a fatuous, garishly got-up clown at whom the world laughed out of discomfort, pity, and contempt. He looked at this figure as closely as he could; but the longer he looked, the less familiar it became. It was not himself that he saw, and he knew suddenly that it was no one.

This is also why Stoner himself doesn't really make assumptions or propose explanations for Edith's behavior or that of anybody else. Any explanation would ultimately reduce that person to a facsimile informed more by preestablished cultural notions which limits their true depth of feeling. A depth of feeling to which Stoner is committed by his fascination with literature, which is the only thing that can truly reveal the farthest reaches of the soul.

(Obviously stereotypes have an instrumental use and it would be similarly unwise, at a meta level, to interpret this all as some typical woke point against stereotyping altogether.)