So you've finally moved on from your narcissist and no longer have to endure the day-to-day abuse, passive-aggressive manipulation, or attempts to make you look (or feel) like the bad guy. Or do you? Most of us know from experience that just because someone is your ex doesn't mean their bad behavior is entirely in the past for you.
There will likely be times that you need to communicate with your ex—especially while you're still figuring out the logistics of the split, and even more so if you must co-parent. And most likely, communication issues were a big part of the reason your relationship didn't work anyway. Narcissists are known for playing games and being childish in communication—ignoring you, manipulating you, just generally making things difficult—and probably making you want to pull your hair out. The moment you realize you're going to have to ask your ex to take your child to their soccer game when it's technically your day, you begin trying to think of any possible alternative to having to interact with him or her.
This is a good instinct. You're wisely wary of the Narcissistic Vortex. Behavior like this is always an attempt by the narcissist to suck you back into their reality—the one in which they are always the victim or martyr and you are the aggressor or villain. They need to remind themselves (and others) that they are still truly special. But because your relationship with the narcissist has ended, they know you no longer accept the version of reality that they want you to believe. For that, they resent you greatly. They will try to draw you back into this reality, and, when you refuse to be complicit in their fiction, they'll punish you for rejecting them.