Has anyone "cured" themselves of toxic relationships with men?

[Clarabumps]

Inspired by another thread I started looking for book suggestions, my best friend has just finished a long toxic relationship with a guy with narcissistic tendencies.
They dated previously and it ended badly and have now reignited the relationship and has ended even worse this time. Every person she has dated has been of a similar type. Every guy that she dates that is nice, she's not interested in. I've tried to support her as best I can. My questions is, if you have stopped dating toxic people, what was the thing that made you stop?
I've suggested counselling and even a 12 step program as I think she's addicted to these types of relationships. I don't know what else to do? She's my oldest friend and I care for her a lot so I can't just unfriend her, that's not an option. Anyone out there came out of the other side of this?

I think staying in toxic relationships (once you know it is) is caused by a sense of not deserving better and fear of being alone.

Once you feel you deserve to be treated well then toxic relationships are not appealing.
I also believe some people are more naturally empathic and can be naive.I put myself in this category.Ex pushed my boundaries but I tended to give him leeway as understood his abusive childhood.He is completely self centred however that's not immediately apparent as he is also manipulative and spins everything.It's only time that reveals these types of individuals but I hope I would be more aware in future.

Would she read "why does he do that" by Lundy..Ir can lead to a lightbulb moment.
The freedom program online may also help.