A description of the process or factors which influence those who do have a relationship with somebody suffering from Borderline Personality Disorder. in Particular some visibility into why those people do not immediately leave the person suffering from BPD.

Few things are more intoxicating than a partner who is brimming with infatuation, or more inexplicable than to watch this same person become resentful and start disengaging for no apparent reason. In a relationship with a person suffering with the traits of Borderline Personality Disorder (BPD) these extreme highs and lows are commonplace.

Source: Surviving a Break-up when Your Partner has Borderline Personality | BPDFamily