Daigakusei no Ore ga Itoko no Onnanoko wo Shiawase ni Suru made

This story is based on Mogami-sensei's wife's experiences, with some fiction mixed in. She is the story composer and planner.
She shows up at his door all battered and bruised, barely stringing two words together.
What could have happened to her at home, that she had to flee to him?