I don't think the causality is clear at all. If he treated his parents the way he treated his girlfriends then his childhood would have been rough no matter how loving they were.
If he behaves like he did in the article: polite at first but increasingly hostile the longer the relationship lasted then he must have been a hellish teenager to wrangle. One part of the article mentions that his anger at his father may have been the result of putting him in an institution.
I'd say that is pretty hard to tell from the hearsay and all these are just speculations, which are okay. We're learning more from these conversations anyway.
I agree that my assumption was based on hearsay. Fundamentally, I don't believe that children who are loved and protected by their primary caregivers shoot themselves in the stomach in an attempt to die.
It is possible to have a who child goes off the rails in a very nurturing and a generally normal family. I've seen cases where one of the many siblings gets to become a sociopath and the family never understands why and they continue to be normal and consistently try to get their sibling back on track. It is clear that abuse in the family doesn't always play a role. But quite often it does and while mental health has a hereditary component, a bad environment only makes things worse.
I recommend Ramsay's movie 'We need to talk about Kevin' to make an idea of how wrong it could go. Surely, it is a movie but it's not too far from reality.
People like this do not behave abusively towards their loved ones all the time, it's pretty on-and-off. The loved one is typically a dependent or avoidant. They remain in the relationship because they need the positive affirmations, and healthy people do not want to be with a dependent or avoidant. So, no choice but to suffer the negativity also.
It's clear that this man developed a personality disorder as the result of suffering abuse as a child.