That sounds frustrating and aggravating.

There are quite a few videos on YouTube about why the narcissist won't leave you alone. Perhaps getting better ideas about what his motives might be could help you feel a bit more emotional distance?

As someone who identifies as codependent, I wonder if you might benefit from looking into doing codependency work (maybe you already have?). Codependency is about detaching from people we have unhealthy attachments to, and living our own lives. Staying in our own lane, and expecting (with stong boundaries) for them to do the same. Detaching is a learned skill, and it can take a bit of time, but it's so worth it to feel the psychological and emotional distance between yourself and the toxic person.

When you stop caring, it won't matter anymore.