An extract of BPD

Someone with a personality disorder is usually a person experiencing chronic inner distress (for example fear of abandonment), which causes self-sabotaging behavior (such as seeking others who fear abandonment), which causes significant problems (such as rage at any perceived hint of abandonment) — in their work lives and/or their personal lives. They may function quite well in one setting, but experience chaos and repeated problems in others. They look no different from anyone else, and often present as very attractive and intelligent people. However, it is usually after you spend some time together — or observe them in a crisis — that the underlying distress reaches the surface.
As interpersonal distress, fear of abandonment, and an excessive need for control are predominant symptoms of personality disorders, they place a tremendous burden on a marriage. Therefore, intense conflicts will eventually arise in their marriages and the divorce process will also be a very conflictual process. In contrast to people who are simply distressed from going through a divorce (over 80% are recovering significantly after 2 years), people with personality disorders grew up very distressed. It is the long duration of their dysfunction (since adolescence or early adulthood) which meets the criteria of a personality disorder.
Usually they developed their personality style as a way of coping with childhood abuse, neglect or abandonment, an emotionally lacking household, or simply their biological predisposition. While this personality style may have been an effective adaptation in their “family of origin,” in adulthood it is counter-productive. The person remains stuck repeating a narrow range of interpersonal behaviors to attempt to avoid this distress.
A personality disorder does not usually go away except in a corrective on-going relationship — such as several years in a counseling relationship. Until then, the person may constantly seek a corrective experience through a series of unsatisfying relationships, through their children, or through the court process. In a sense, untreated personality disorders don’t fade away — they just change venue.