Narc couple?

Hi,not sure if this is the right place for this post but hopefully I will still get some response/insight.
Ever since I discovered my ex was a narc, the topic of narcs has stayed with me. I have stayed no contact for years now and no longer feel that particular narc is a threat. However, I keep "running" into other narcs or identifying people as such.

I had a female friend who I am pretty sure has at least some narcissistic features. The friendship ended a few years ago, it was a mild D&D from her part, whatever, I don't care anymore. She's a coworker as well and we started talking recently on a friendly basis but I am definitely not interested in a friendship anymore. She was having relationship problems and described them to me and some of the stuff sounded as if her husband was a narc as well (again probably not a full-blown narc).

So here's my question: do narcs ever end up dating each other? Does anyone know of relationships of two narcs that actually work? These two people in question have been together for 15 years, most of the time quite happily. Like I said, they most likely aren't full-blown narcs but definitely display some of the traits common to narcs.