What is the most common mental disorder that women who become involved with Psychopathic males have?

I've noticed that women who end up with Sociopathic males sometimes will try everything to make their partner happy & even take on some traits of sociopathy as well. Can people without APD develop it from being around another with APD or is it just a case of extreme codependency or Borderline Personality Disorder? Like in the case of Karla lka & Paul Bernardo, Karla may have been a Psychopath as well but to me at least it looks as though she would just do anything no matter how cruel, vile or unconscionable it seemed just to keep Paul happy. What mental disorder would cause this type of behavior?