First, learn everything you can about the disorder. Then take care of yourself first. BPD is presently incurable so there is not much you can do besides being careful about your own behavior and avoiding things that trigger BPD. It important to remember that the more central you are to her life, the more she will fear abandonment and the more likely it will be that she will start hating you (devalue you). With a BPD, unconditional love can be counterproductive. Below, i am attaching a summary of what BPD is. I hope it helps to showcase behaviors you should avoid from your end.
Borderline Personality Disorder (BPD) is a hereditary, genetic condition that significantly affects emotions, sense of self, memory and interpersonal relationships. Studies reveal extensive differences in brain structure and function. BPD is often triggered from the interplay of genetics with trauma during childhood. It is suspected that during early childhood, increased levels of cortisol caused by stress (trauma) permanently change the brain structure and function of those genetically predisposed to it (such as increased gray matter in the amygdala area, among other things), causing BPD. While there is no cure, BPD is very treatable with Dialectical Behavior Therapy that was specifically designed for people with BPD (by a person with BPD) and can give someone the tools to recognize and manage the symptoms.
More specifically, BPD causes intense emotions that are difficult to control and manage including Fear of Abandonment which is central to BPD. BPD is primarily noticed through interpersonal relationships:
Persons with BPD (PBPD) feel all emotions intensely, therefore, when they like someone (either in friendship or romantically) PBPDs will love that person intensely. If the other person reciprocates then they will both be enmeshed in a very intense and personal relationship. When a PBPD loves you, they will make you the center of their lives. This phase is called “Idealization” and the loved one is viewed as “all good”. PBPDs also feel intense fear of abandonment - and in order to avoid any possibility of abandonment happening - they will unconsciously suddenly start to hate (“devalue”) their loved ones in a process called Splitting (which will also completely change their memories of such a person).
Splitting occurs primarily against those people PBPDs feel like “they cannot live without”. At the suspicion of real or imagined abandonment, suddenly (overnight), the loved one will be viewed as “all bad” and all their behaviors become suspect with malevolent ulterior motives. The entire relationship is completely forgotten and replaced with an alternate reality where the former loved one was always “all bad” and the two were never enmeshed in an intense, loving and personal relationship. This phase is called “Devaluation”.
It is important to note that BPD causes fragmentation of memory including, lack of object constancy, lack of whole object relations, “emotional amnesia” as well as outright False Memories (things that never quite happened, but feel as true to PBPDs as anything else). This peculiar problem with memory means that PBPDs only remember others based on their last encounter and continuously color the entire relationship based on each last encounter (i.e. they cannot link the past with the present, because of the lack of object constancy, they can only live in the present). Furthermore, PBPD memories are based on their present feelings and not the actual past (“what people need to understand with borderlines is that their emotions and feelings dictate their reality…..instead of facts.”). A distorted view and understanding of reality is one of the major issues of BPD. Without treatment, PBPDs are generally unaware that their memories and perception of reality are distorted or that something is wrong.
If a PBPD Devalues you, then you will be remembered as always having been a terrible and evil person who they don’t particularly like (even though up until yesterday you were the center on their lives and could do no wrong). Any attempt to remind an untreated PBPD of the past will cause them confusion and cognitive dissonance. Untreated PBPDs will ultimately rationalize their behavior even against overwhelming facts. For PBPDs, how they presently feel about something, makes it the absolute and only truth.
Once Devalued, the loved one will notice a very drastic, sudden change in the PBPD’s behavior towards them– the person who was extremely loving yesterday and had made you the center of their life, now treats you like a persona non grata for no apparent reason while denying anything is different. The Devaluation phase completely erases the loving and close relationship. The PBPD will be unable to remember that they once had strong feelings for you.
At the exact moment of Devaluation, PBPDs will start planning and implementing their exit strategy from the relationship (since they now hate/dislike the other person). Typically that involves a lot of rationalization as well as the elaborate manipulation and gaslighting of the former loved one that PBPDs are known for. Rationalization, manipulation and gaslighting are not done consciously or with malice, but are simply the result of whatever the PBPD feels is true at the time. As mentioned previously, PBPD perception of reality is based on present feelings (and during Devaluation, they will believe, beyond any doubt, that the former loved one is a bad person with ulterior motives).
Furthermore, a person with “Traditional BPD” will express intense bouts of anger and rage towards the former loved one, while a person with “Quiet BPD” will become cold and distant. (Note: Quiet PBPDs experience the same hard-to-control intense anger as Traditional PBPDs, but instead of expressing those feelings outwards, they are internalized).
Because PBPDs fear abandonment, they may still try to keep the (now former) loved one around in the famous “I hate you, don’t leave me” phase. In this phase the PBPD will be emotionally distant and even mean to the former loved one (“I hate you”), but at the same time they will also take steps to convince the former loved one not to disappear from their life (“don’t leave me”). Needless to say this is a very toxic phase. Alternatively, a PBPD may themselves suddenly disappear from the former loved one’s life and reappear later.
It’s possible for the PBPD to slowly love the devalued person again, starting the cycle of idealization and devaluation all over again. Until the PBPD receives treatment, devaluation of loved ones is inevitable and at some point, this cycle will break into permanent devaluation.
It is important to note that PBPD s Idealize and Devalue themselves as well as others. They may confident and proud one day, but the next see themselves as terrible persons who do not deserve love, friendships or success in life.
BPD causes a host of other symptoms, such as: Getting angry or upset very easily and finding it difficult to calm down, strong feelings of emptiness, impulsivity, drug use to manage the intense emotions and feelings of emptiness, self-destructive behaviors like sabotaging close relationships or even self-harm, incorrect perception of reality (“delusions”), unstable sense of self (PBPDs have a hard time knowing who they are or what they like and dislike), difficulty to admit fault (“projection” of fault to others), disassociation from reality under stress (and/or hallucinations), and ultimately an extremely high rate of suicide (up to 70% of PBPDs will attempt suicide).
BPD is a serious and dangerous condition and one of the four “Cluster B” Personality Disorders (Antisocial, Narcissistic, Borderline, and Histrionic) that are characterized by dramatic, overly emotional or unpredictable thinking or behavior. It is imperative that PBPDs receive professional treatment. Unfortunately, many psychologists appear to lack to skills to properly diagnose BPD and it is often misdiagnosed or even left undiagnosed. Besides Dialectical Behavior Therapy which is absolutely necessary, it is said that yoga, meditation and breath-work can help manage the intensity of the BPD emotions.
It is also important for the loved ones and former loved ones of PBPDs to seek help for themselves. The trauma of suddenly losing a loved one for no apparent reason often causes PTSD and/or other mental health issues. For this reason, people who have been through a relationship with a PBPD are often called BPD survivors.
Once someone is aware of what BPD is, it is extremely easy to spot due to the intensity of the interpersonal relationships and the sudden devaluations that follow. It is through these interpersonal relationships that high functioning PBPDs often realize that a problem exists.