They have been together for a long time. As in any codependent relationship, there might have been oversharing at one moment. I suspect that he could be merely manipulating her all the time. But, what do we know? Current situation is surely not expected or normal, but specifically this makes me wonder why she stands by him.
ETA. Didn't ES mention in one of her texts CS treating herself badly, too? The kids, and her? One really wonders what was happening in that family. CS's behavior is that of a raging addict, but i am slow to pass judgment on ES, not because i condone her...just counting a medical school, residence, work, three children. She was not a weak woman. She might have either felt constant fear, or was cornered. Why, remains to be seen.