From your description about her, I suspect that she is suffering from Personality Disorder (probably Borderline Personality Disorder). It is condition where person (more common in female) shows certain personality traits, possessiveness, aggressiveness, suicidal threats, attention seeking behavior, suspiciousness etc are few of them. They are one of the most difficult people to stay with. You are required to consult psychiatrist even if she may not accompany you. You may take online counseling for your day to day problems with her.