They want people to attack each other, insult someone who they don't like, just so that they can feel special and in control.
Yes that is narcissism and it's believed to be more common now than ever.
And narcissists destroy people they don't like.
They control people who otherwise don't want to abuse others or hurt others and turn them into a co-narcissist.
Narcissist has no empathy as to feel happy, they want to just reduce the person they compete with to 0 and so they will go at any lengths to control this dynamic. So if a narcissist is around, they don't care it's your life partner, they see them only as someone they don't like and so they will display no empathy for them.
Narcissists need complete control of you and life partner and their time with them, in their mind threatens this bond and so they can absolutely make you ignore your partner to the point they feel pointless being in your life and completely isolated.
It's difficult to let go of narcissist abuse and you may very well be a victim too who now just doesn't know.
Seek therapy at IWill, as an individual or as couple, to know how you may be allowing abuse and neglect to continue.