This sounds like a need to repeat your trauma. Something like a girl who grew up in an abusive household finds a man who beats her.

I'd definitely recommend looking for a good trauma focused therapist and working on your self worth. What you're doing is a cry for help. Why do you fantasie about being completely mentally broken? Because you crave help and need someone to be with you. So you actually don't crave being broken, you crave the help and support you deserve. Please try to find someone who can provide that for you.

I truly wish you all the best and I understand you. I'm not exactly the same, things manifest differently in me, but my thought process can be very similar to yours. Good luck!