I'm just gonna say, Saeko's issue seems pretty serious, like "maybe I should see a counselor" serious. I'm sure there's gonna be some backstory that will come out of this, but in any case it doesn't strike me as something you can fix with simple will or even just talking. Dealing with stuff like that takes work, time, developing strategies, not something that can be made to disappear.
This is the sort of thing people see relationship counselors for. This breaks relationships all the time.
I think Sae is being too hard on herself, too. She's trying. It's not easy.