Yes I think you're right in saying that most healthy people wouldn't even think twice about a relationship with a person displaying a high degree of N traits or even think twice about them other than to avoid them or giggle perhaps when I recognise some aspects of myself that I always thought was one of my strengths but now seems juvenile. I've actually found the more balanced I've become in my thoughts about myself and what is important to me, now I've been dealing with my core issue, of low self worth, the less N traited people I've encountered. I think this is mainly because I don't need the same level of attention that I used to or the same types of distractions so I'm not drawn to the same places or distractions and can happily stay at home and self reflect without wasting energy on getting attention or winning every situation. So, is narcissistic behaviour contagious if you have that inner core issue of low self worth. For myself, I found it definately was like a virus that got into my brain. And that NPD partners wanted it to stay right there thank you very much. Don't you move a muscle in your brain! That's how I view it, in hindsight.

I wouldn't say I'm no longer NPD/BPD but I would say I'm a far more self aware and better functioning one, and when I say one I mean I'm able to incorporate the better parts of both NPD and BPD into one package. Because there are some amazing qualities in every PD.