It's an assumption that a wife that stays with her abusive partner has " a relationship before the abuse started, love, attraction, good memories". In many cases, that isn't the scenario at all. Many people marry someone who is already got them knee deep in trauma bonding.
And yes. There's an incredibly significant amount of trauma bonding that would occur just based on the fact that he murdered her parents in front of her and literally held her life in his hands. Trauma bonding is literally a means to survival for people in horrific situations. It upsets me greatly when people use it to imply that the victim was supportive of their captor or in some way complicit to their abuse. I believe that by discussing it can we stop that stigma and better support victims,
I like your use of "fortitude". I was looking for a word that didn't have implied expectations (that I avoid using with victims) and you nailed that perfectly.