It sounds like your partner might have a form of Post Traumatic Stress disorder (PTSD) and/or Battered Wife Syndrome. There is loads of research and information about both of these disorders on the web, but a good place to start might be the American Psychological Association site at www.apa.org
In terms of treatment for your partner, I would suggest counseling but with someone who specializes in the treatment of PTSD. She might also benefit from a low dosage of an SSRI medication such as Prozac, Zoloft, Paxil, etc. Once she gets connected with a psychologist and/or psychiatrist, they could determine whether or not one of these medications would be right for her.