This can happen before, during or even after the relationships end. Their sensitivity to criticism is unchecked and the smallest inkling of having someone disagree with their perception can cause a lashing out in rage, a silent treatment or discards over simple misunderstanding or over individual preferences.
The narcissists deems themselves smarter than anyone in their circle and if you question his motives, he lashes out and disparages your character in front of many. Some will even discard you in public, shaming you for having a viewpoint separate than their own.
They will boast how they are the leader and are open to differences of opinion, yet when someone dares to disagree, they are thrown out of the family or group and labeled as crazy or stupid or deranged.
Only the narcissist can be the lead/god. Anyone else is just blasphemous. It isn’t easy to run a company let alone a family with someone who thinks they are right from the moment they “Wake, until the moment they go bed”. Heal anyways Survivors.