The venomous side of human personality is a dark place. When sadism is thrown in the mix, the human personality becomes pitch black.
Before today, sadism never entered your realm of possibilities. Maybe because you associated it with physical pain & not emotional pain. You also never realized narcissism is divided into catagories; classic narcissist (typical; what you think when you hear "narcissist"), vulnerable narcissist (appear to love attention, but in reality, hates it), & the most extreme, malignant narcissist (“the quintessence of evil”).
Unfortunately, you chose door #3 & it has a name; narcissistic sadism.
Narcissism drove the control issues, manipulation, deceit, bragging of accomplishments, entitlement, & much more wretched behavior you despised. You knew why those things were present; because narc.
What's been on your mind & chronicled in your journal, is the desperation to understand how/why a person not only feels zero remorse, but seems to actually enjoy causing both sexual & emotional pain. How can a human show no empathy to the mother of their children after they've annihilated their life by sexual deviency & grade-A asshole behaviors. The vindictiveness, inability to communicate if your opinion was different than theirs, & the very present desire to screw your world up makes sense, now; because sadist.
This one is going to take a little bit to digest.