Cut them off when they start to get nasty. And they will get nasty. Narcissists may love bomb you for a short time and try to gain (or in my case, regain) your trust, but make no mistake: they ARE out to get you. You can NOT trust them. They will NOT change. Ever. No amount of reasoning with them or logic will change the way they are or the way they will try to use you and put you down. YOU are ALWAYS wrong. They are ALWAYS right. No exceptions. They’re not stupid: they actually DO know you ARE right, but knowing you are right makes them VERY ANGRY. They will start hurling insults at you and making your life miserable.
There is only one solution at that point: CUT THEM OFF. It may not be possible to go No Contact in certain situations (particularly if a child is involved), but if you can’t, you can cut them off or refuse to speak anymore to them until they are CIVIL and treat you with RESPECT. Eventually they will have to stop insulting you and at least pretend they respect you if they want something from you, otherwise IGNORE THEM and their demands. If they want something from you badly enough, they can ask for it RESPECTFULLY. If they can’t or won’t, they will just have to LIVE WITHOUT IT.
And of course, you can always just say NO. Saying NO won’t kill you. If it pisses off your narcissist, they will just need to deal with it. Do NOT let him (or her) manipulate you into giving them something you don’t want to give them.
In reading back over the two text conversations with my ex, these are the things I have learned. My narcissist won’t ever change. Your narcissist won’t either. Do NOT let them fool you. They’ve been trying to make a fool of you all along.