You have been a great source of narcissistic supply, but you finally figured out that you have been dealing with a narcissist.  When they realize that you see this, there will be backlash.  That is because they know that they will be unable to fool you anymore and won’t be able to continue their narcissistic supply from you.  You are now interfering with their addiction, which is the supply of attention, admiration, power and control that you gave them.  They will be in withdrawal.  You might see a no gap transition, meaning they will quickly find another source of supply, maybe immediately into another relationship to stabilize their inner world.  You will also see narcissistic rage, which looks completely unfamiliar and like pure evil.  Look out for smear campaigns, verbal, emotional, mental and even possibly physical abuse, and of course, the victim mentality.