The narcissist ended it, and they walked away. It's likely that they pushed you until you had no choice but to say you were leaving. Whatever happened, there was a breakup, and it was all because of the narcissist.
You going means you've done something they never thought you'd do next: you blocked them.
I'm talking socials, phone, email; every little way they could creep back in has been made impossible.
The narcissist? They're going to lose it.

1 The narcissist will never leave
The surprise most people experience from the narcissist after you've blocked them is that they don't tend to just go away.
Blocking feels good, and I believe is completely necessary if you want to move on and heal from this traumatic experience, but you aren't going to get that right away.
Seems crazy though, doesn't it? I mean, they end the relationship, and you block them to seal the deal, and they in response end up losing it.
Why is that?
Let me tell you how this works:
The narcissist is like a toddler. They end relationships like the biggest, most dramatic toy being thrown across the room.
The aim of this game is to see what happens once they do lose it. Their expectation is that you will jump up and scramble to fix it. They genuinely want to see you beg and wait by the phone for them to call, but that's not what you're going to do, is it? Is it?! I HOPE NOT!

When you block them, you're telling them that no begging or waiting is going to happen, in fact, you're done and you're walking away from it all. Your silence is a pain to them, and they cannot stand the idea of you refusing to give them any more attention from here on out.
The narcissist's plan was not for you to disappear first.
2 Your blocking is a power move like no other
And it won't be expected, let me tell you!
Blocking a narcissist takes some strength, because you'll be fighting with your past. That's a past that reminds you, "You wanted this. You wanted to stay and hope. Things might change. Just try to be more understanding and patient. Give them what they want and it will all work out."
Eventually, you get to a point where you know nothing will change, and so blocking really is the full stop after a very long and painful sentence.
See also 5 Creepy Things Every Narcissist Hides Somewhere in Their HouseWhat you're after during this blocking stage is refusing the narcissist access to you.
Sounds great, doesn't it? This is a person who has made your life hell, and now you get to take control for the first time in what feels like forever. If you allow that access, you're allowing them into your personal space again. You're letting them see the pain they put you through whenever they feel like it, and that's not fair.
You're starting to see that, and so blocking is the only sensible choice. The narcissist then, isn't able to just jump in and ask how your day is before drifting off and blanking you for two weeks.
You block them, and that door slams shut in their face. You keep them blocked, and that door stays locked.
That's what you want: that's the point where you get to start to rebuild your life.
As for the narcissist, they won't know how to handle that one bit.
3 What goes through the narcissist's head in this moment
What do you think happens? I'll give you a clue...
"Why won't they just respond?"

"Why are they not replying?"
"Why is my message not going through?"
"This makes no sense, I ended it, so they should be upset!"
"Let me just check their profile..."
Oh dear, can you not reach it? Is there only one tick, or 'sent' up against everything you're trying to send? That'll be because you're blocked!
The wall is blank, and that's down to the fact that you wanted to make yourself totally unreachable.
The narcissist is far from bothered at this point as they struggle to know what to even do next.
You'll shock them when you block them!
The panic won't be difficult for them to feel; it'll be pretty much instant as they realize the game has turned on its head, and the unthinkable has happened. They won't be used to that, and seeing as you are also new to the whole blocking thing, I do need to point out that the narcissist needs to remain blocked.

4 Someone will let you know the narcissist's reaction, trust me
Through someone at some point; it'll happen. You'll hear everything about the narcissist's response to your blocking and it'll be purely down to the fact that the narcissist can't get to you, so they find other ways to do it.
This is typical of these people, who will stop at nothing to ensure their thoughts reach you, so just as you feel free and happy, you're immediately weighed down again by their toxicity, even if it's second hand.
This means mutual friends will come along and offer their thoughts to you, mentioning the narcissist casually. The text from that number you don't recognize will reach you. People will post things aimed at you that will get to you and it will be the narcissist pulling the strings.

"Just say that I don't feel angry, I just think it's pretty immature to block me."
"It's much more adult-like to remain on good terms."
"I'm actually quite worried about them. Are they doing okay?"
Sure, worried, that old trick. The only thing a narcissist is ever worried about is anybody stopping caring about them. They're worried that you're okay. Other than that, they're good to go!

5 When nothing else works, you can always rely on blocking
That's what I think the good thing about blocking is. If you want to continue this dramatic back and forth with the narcissist, just leave yourself readily available. If you want to keep exhausting yourself, then allow yourself to keep explaining why you did this, or said that, or tried this.
Everything you do that results in a response hands them the power to twist it into whatever they want it to look like.
See also THIS is What Makes NarcissistsBlocking? That's a totally different story. Blocking means you have given the narcissist nothing to work with. They can't misquote silence, right? That's where you want to leave it, and that's where becoming this mystery helps you and improves your wellbeing almost overnight.
6 They're losing their mind? I say, "Let them!"
Let them, for all you're worth, just do it! Let the narcissist lose their way of thought because they are dealing with something out of their grasp.
This is about protecting your peace, and if you can't do that, then what can you do?
The narcissist ended it, remember. They told you it was over, and rather than run back to them begging for another chance, you shrugged and said, "That's fine by me. Have it your way."
They did not anticipate this, and you're bothering them with your silence and stance on what you'll tolerate.
