You use the gray rock method on them. Essentially you do not emotionally engage with them, be as boring as possible so they move on to other targets for narcissistic supply.

I was tangled up with a narc for over 18 years and didn't know what I was dealing with. It's one of the most soul-crushing things if you don't know what's going on. When figured out what I was dealing with, it was like waking up out of a coma.

Try the Pieter Hintjens psycopath book. Overlook that he uses a non-clinical use of the word psycopath. Pretend he instead wrote vampire, and read for the content. He gives strategies that do not involve leaving, and that seek to build you to a position of strength so your antagonist has to bend. (I have not had cause to test any of it, so no annecdotal endorsements herr)

Leaving is the only option.