I will say this… 1. She trusted the child psychiatrist because she knew 100% that doctor wouldn’t share intel to the people paying her and thus was an actual safe space 2. Being in a marriage where one spouse has a massive secret and it feels like an invisible elephant in the room that only both of you can sense and you spouse denies sensing it or having it at all WIIL ABSOLUTELY drive a sane person crazy.

If you want to get into psychiatry, then let’s delve into the subconscious here. Betty’s gut knew something was off. Hence the scene in bed when she looks at Don’s head and wonders who/what is in there.

Maybe I’m biased bc I’ve experienced it, but it’ll make you go batty. Don basically was gaslighting Betty the whole time.