I’ve heard it many times. I had break ups prior, yeah they were sad and it took time but the break up with my narcissistic ex is really hard, it’s been years.
Why does it take such a toll? I found after I left him everything suddenly felt so much worse, like I experienced the relationship again but worse. I never realised how scared of him I was and how much I appeased him. I became a wreck for a while, too scared to go out etc.