For how much research Brandon did to write about DID in Shallan's arc and depression in Kaladin's arc, I feel pretty certain that he did a good amount of research about abuse. I want to answer the question of why does Gavilar act that way by talking about the real life reasons for domestic abuse. For a bit of context, I work a lot with people who have been convicted of domestic assault. I would say about half of the clients that I work with have been incarcerated for either strangulating their partners, violating protection orders, or after being convicted of domestic assault on multiple occasions.
I want to state one thing first - mental health issues and substance abuse do not cause domestic abuse. It can exacerbate it because people are more likely to make impulse decisions because of these factors, but it does not cause it in 99% of cases (yes, there are a few outliers, but we don't see any evidence of heavy enough substance use or severe enough mental health problems for Gavilar to be one of those outliers). I would also add that the extreme power differences between Navani and Gavilar. That's something that Gavilar points out to Navani in this chapter
Right now, the best model for understanding domestic abuse is the Duluth model. This model suggests that domestic abuse is all about the abuser maintaining power and control in the relationship. This model has produced both the Power and Control Wheel as well as the Equality Wheel. I can't link to either as I have not posted enough, but I recommend looking them up. Now, you can argue that it is flawed or that another model is better, but after working with many batterers, I feel that it describes the reasons behind domestic abuse well. The abuse in dv (or domestic violence situations) is often not about lashing out or the batterer misdirecting their anger, but it is used as a weapon to get their way and maintain power in the situation. For example, I have had situations where I will be having an calm conversation with someone and I will tell them to do something they don't like. In an instant, they will be screaming at me as a way to intimidate me into changing my mind. Most batterers have learned that the most reliable way to get control of a situation is through violence, which might be why people with histories of domestic violence are more likely to engage in violence against law enforcement and perpetrate mass shooting. This also fits with what we know about Gavilar. He took control and maintains control over his kingdom through acts of violence. In the end, there isn't really one event that can cause a person to become an abuser. It has more to do with an need for power and control and the willingness to use violence to fulfill that need.
