I feel you, my friend either when it comes to having been abused by a covert narcissistic ex-partner or how you feel about JD and AH.
Having been raised by a narcissistic mom (a tricky combination of self-righteous, communal, ethical, covert and moving to vulnerable (the victim) while aging --the easiest way to extract tons of supply), I not only sympathize but also empathize.
I've known several narcissistic ex-partners which comes without surprise if we know anything about the attachment theory (we're subconsciously attracted to the type of bond we're familiar with in our household).
The last one was a malignant/psychopath with no antisocial traits (the predator feeding on others' suffering without any remorse). He was the trigger of my re-birth and for that I'll never thank the Universe enough!
If I may add something to JD and AH case, I'd say that JD is also a victim of a narcissistic family system (too frequent sadly enough and that's why I deeply believe psychological education should be the number one priority at school and that a system to diagnose the household toxicity needs to be put in place.
I even believe narcisisstic parents (among other pathologies from the Cluster B group whose core is narcissism) should be prohibited by the LAW from giving birth to kids or
keeping them when diagnosed.
All toxic family systems kids need coping mechanisms to survive and the overall insecure attachment style would set the tone!
Appealingly, all JD "decent, kind-hearted, and people of integrity" ex-partners and friends agree on how gentle, humble and sweet he is (I can effortlessly witness).
That is, it seems to me that what happened with AH is "reactivity" to harsh abuse. The more limiting beliefs we have while diving into life, the smaller the gap between the stimulus and response would be and the more reactive we'd be while dealing with manipulation and abuse...
In summary, perpetrators/antagonists like AH are INTENTIONALLY violent (as a way to gain control and feed on their victims), while protagonists like JD are violent (always without reaching the level of a jerk) only as a subconscious reaction. The difference is huge, I suppose!