I agree with MsLady that BPD (or Emotionally Unstable Personality Disorder, EUPD, as it is no less clumsily named in the UK) sounds more likely.

While I read material on NPD I often feel accused and doubtful myself, and find myself running through what I've previously read, in my mind, to try and ascertain I'm not incorrectly diagnosed, or not guilty of the traits I've suffered at the hands of three others with almost certain NPD.

I think this happens because there are shared traits but more importantly shared biographical details. Someone with BPD and someone with NPD can have been through similar things in childhood but end up dealing with them differently. If I had had the misfortune to be very good looking I might by now be a dreadful case of NPD. Luckily I look a bit rough.

But, even if NPD turned out to be the correct term for you, these disorders are points on a continuum, and describe the faults of not machines but human beings. Even in the most damaging cases, someone with NPD isn't like a cartoon villain, like Skeletor, cackling away at evil acts. There is always room for manoeuvre - the egg-referencing part of that word's etymology being very pertinent here - and you are fortunate enough that you may have reached saturation point as regards the consequences in your life. I find that quite moving as a possibility because I still miss at least one of the people I've encountered with the behaviours and need to believe she can save herself.

Just stick with the therapy, as far as money and time allow, the reading and discussion here, and keep trying to be mindful in how you deal with people. Twenty-five years ago, and maybe even five years ago, I did not know how to deal with people when things went wrong, and ended up a bit of a doormat. Someone with similar biographical details to me but who took a narcissistic path - or it took them - could end up dealing with social friction in an aggressive-defensive way that has narcissistic aspects to it. The medical terms aren't perfect and don't cover every permutation of dysfunctional behaviours, and perhaps you are more free in having behaviours that possibly straddle NPD and BPD behaviours. A lack of literature bespoke to the specifics of you personally and a lack of a fixed medical term might help underscore that your own will and compassion can decide how you are in the future, whether that might be a year away or five.

As society asks of us an unhealthy mode of being, a dehumanised way of living, I believe some disorders can in fact be a mid-point between an inauthentic way of being and true freedom. In my view, 'having' EUPD for example is kind of a privilege, if a person works with it conscientiously and carefully. Being unstable isn't great, but being emotionally alive is preferable to being an automaton, such as are the people who actually cause disorders, from unthinking parents to partners to narcissistic presidents. After all, it is because we were once vulnerable and wholly, emotionally human that the perpetrator relevant to our lives was able to take advantage of us.