ExH has or had an internet alias, and a Jekyll and Hyde type alter ego in RL.
My exMIL had a horror of anyone else's illness. She openly mocked her own late MIL after visiting her in hospital where she was dying of cancer, mimicking things she had said during the visit, while my exFIL drove home, listening to her speak so cruelly of his own mother. Another time, when I had a mc at Christmas at her house (we were staying there for a few days), she was really annoyed that I followed doctor's orders and wouldn't get up from where I was lying to sit at the dinner table my mc ruined her Christmas. exH told me that if he or any of his siblings were too ill to get up out of bed during their childhood, they weren't fed either you could have a drink of water but if you wanted soup or crackers you had to get up and sit at the table.
My exH managed to make a death in my family all about him. The only thing he expressed any strong emotion about was the fact that he was so late getting to the airport that he almost missed his plane. Fact is, he made his plane, but he ranted on and on and on and on about my family and how they had kept him from getting to the airport in extra good time (he has a bee in his bonnet about 'punctuality' which means getting somewhere far too early) A few weeks later he started mixing whining about the plane and his old fallback position, the state of the house. It was not pleasant to have lost a dear family member and then be attacked with anger and impatience and name-calling a short time later about how little I had managed to achieve on the home front during the day. ExMIL managed to make a death in her family into "the Me show" in the memorable words of another SIL -- not MIL's DD, but BIL's wife. ExMIL definitely has Histrionic PD, and probably NPD too.
I actually took to recording his episodes of rage from time to time -- he alternated between giving me the silent treatment and flying off the handle. He would glower at me as he walked through the house, shoot me dirty looks if he entered a room that he didn't consider tidy enough. I found that recording these episodes helped me to stop doubting my impressions of them. I never threatened him with my memos to file in any way, they were for my own mental and emotional health purposes only.
ExH couldn't take any kind of criticism from me. He once asked me, after just a few years of marriage and before I had joined the dots to come up with the real picture, to list his faults and personality defects for him (top of the list was arrogance but there were many more); after that day, he didn't want to hear any kind of criticism from me. If I complained about his temper, he would fly into a rage, excuse himself on the grounds of my terrible housekeeping/ negligent style of parenting/ over-attachment to the DCs/ mistakes in the chequebook register/ blah, blah. blah. He always had unassailable reasons for his tantrums. He would walk out of the house rather than let anyone else speak words of reason or express their truth. If I had feelings and the temerity to express them, I got called names, b and nag being his favourites.
Trying to get my pov through to him became well-nigh impossible. As an example, he got it into his head one day that the DCs' bedrooms needed blinds, so I measured the windows and made a list with the correct blind measurements for each one. The job had to be accomplished that day, according to him, so I pretty much dropped everything to get the measuring done before he took off in the car. He came home with blinds that were the right size for three of the windows, and too small for the other one. He took it very personally when I pointed out the inches of daylight on either side of the small blinds, called me all sorts of names. He had a habit, if he was engaged in any sort of project, especially home improvement or maintenance, and I made a suggestion, of growling through gritted teeth, "Don't tell me what to do." Very alienating, and I felt more and more leery of him over the years. Conversation, let alone real communication, became less and less possible. I felt completely silenced.
I read somewhere (I think on a Sam Vaknin site, Buzzle.com -- vague memory) that empathy is the foundation stone of morality. To empathise is to have a modicum of humility, imo, to couch it in terms of values or morals. Humility allows you to have a sense of perspective, an insight into your own reactions and perceptions as well as into those of others. Ns lack this quality.