Craig, I suggest you see a psychologist to obtain a professional opinion on what you're dealing with. I share u/Reverend_Vader's concern that you are describing many warning signs for BPD (borderline personality disorder). That's why I asked you about the 4 behaviors, all of which are red flags for BPD (which my exW suffers from).

I caution that BPD is not something -- like chickenpox -- that a person either "has" or "doesn't have." Instead, it is a spectrum disorder, which means everyone occasionally exhibits all BPD traits to some degree (usually at a low level if the person is healthy). BPD traits are primitive defenses that, when used appropriately and in moderation, increase our chances of survival.

At issue, then, is not whether your GF exhibits BPD traits. Of course she does. We all do. Rather, at issue is whether she exhibits those traits at a strong and persistent level (i.e., is on the upper end of the BPD spectrum).

Importantly, I'm not suggesting your GF has full-blown BPD. Only a professional can determine that. Instead, I'm suggesting you consider whether she may be a person with many strong BPD symptoms (i.e., may be a "pwBPD").

When we first began dating, she was great.

Craig, most pwBPD are good and caring individuals. Their problem is not being BAD but, rather, being UNSTABLE. Indeed, a pwBPD typically exhibits the warmth, spontaneity, vulnerability, and purity of expressions that otherwise are seen only on the faces of young children.

This is why pwBPD usually are very easy to fall in love with. It thus is not surprising that 3 of the world's most beloved women -- Marilyn Monroe, Judy Garland, and Princess Diana -- all had full-blown BPD if their biographers are correct.

Her tantrums are almost excusively reserved for me, her sister, and her friends.

Craig, the vast majority of pwBPD are "high functioning" -- i.e., they typically hold jobs and generally get along fine with coworkers, classmates, casual friends, and total strangers. None of those people are able to trigger her fears of abandonment and engulfment.

There is no close relationship that can be abandoned and no intimacy to trigger the suffocating feeling of engulfment. Hence, with most pwBPD, the strong BPD symptoms usually appear only when someone draws very close to the pwBPD.

This is why it is common for high-functioning pwBPD to do well in socially difficult jobs such as being a social worker, nurse, professor, salesclerk, or doctor. And this is why most pwBPD can be considerate and friendly all day long to complete strangers -- but often will go home at night to abuse the very people who love them.

My GF often yells at me over innocuous and benign statements.

If your GF is a pwBPD, Craig, she carries much anger inside from early childhood. You therefore don't have to do a thing to CREATE the anger. Rather, you only have to do or say some minor thing that triggers a release of anger that is already there. This is why a pwBPD can burst into a rage in only a few seconds.

Moreover, the key defining characteristic of BPD is the inability to regulate one's own emotions, resulting in unstable behavior. This is why, outside the USA, most countries call this disorder "emotionally unstable personality disorder" (EUPD).

She attacks me... I have bite marks on my arms and forehead. I have a broken pinky finger. I have scars from her clawing at me.

Craig, a substantial share of pwBPD never physically abuse their partners. Many of them do, however. This is why more than 30 empirical studies have found the physical abuse of a spouse or partner to be strongly associated with BPD.

And this is why "Intense, inappropriate anger" is one of the 9 defining traits for BPD. Indeed, the terms "anger," "impulsive behavior," and "unstable" appear in 4 of the 9 BPD Symptoms.

She tried to stab herself to death in front of me... She has huge scars all over her body from self-harm.

Craig, another one of those 9 BPD symptoms is "Recurrent suicidal behavior*, gestures, threats, or self-injurious behavior such as* cutting or hitting yourself." Significantly, of the 157 mental disorders listed in the American DSM-5, only BPD has both suicidal thoughts and self-harming behavior like cutting included in its list of defining symptoms.

She is constantly telling me she loves me.

If your GF is an untreated pwBPD, she likely does love you. Indeed, a pwBPD is capable of loving you very intensely -- but it is the very immature type of love you see in young children.

This means she will occasionally flip -- in only seconds -- from Jekyll (adoring you) to Hyde (devaluing or hating you). And a few hours or days later, she can flip back again just as quickly. These rapid flips arise from a primitive defense called "black-white thinking."

Like a young child, a pwBPD never had an opportunity to learn the emotional skills needed to handle two strong conflicting feelings (e.g., love and hate) at the same time. This means she has great difficulty tolerating ambiguities, uncertainties, and the other gray areas of close interpersonal relationships. She thus will subconsciously split off the conflicting feeling, putting it far out of reach of her conscious mind.

With young children, this "splitting" is evident when the child will adore Daddy while he's bringing out the toys but, in only a few seconds, will flip to hating Daddy when he takes one toy away. Importantly, this behavior does not mean that the child has stopped loving Daddy. Rather, it means that her conscious mind is temporarily out of touch with those loving feelings.

Similarly, a pwBPD will categorize everyone close to her as "all good" ("with me") or "all bad" ("against me"). And she will recategorize someone from one polar extreme to the other -- in just seconds -- based solely on a minor comment or action. This B-W thinking also will be evident in her frequent use of all-or-nothing expressions such as "You NEVER..." and "You ALWAYS...."

In every argument, she claims I don't love her anymore.

If your GF is an untreated pwBPD, Craig, she is so immature that -- like a very young child -- she cannot perceive "object constancy" -- i.e., she cannot see that your love for her is essentially unchanged from day to day.This is why it is impossible for you -- through sacrifices and gifts -- to build up a store of appreciation and good will on which you can later draw during the hard times. Like a young child, her perception of you is fully dictated by whatever intense feeling she is experiencing AT THIS VERY MOMENT.

Hence, trying to build up a lasting store of appreciation is as futile as trying to build a lasting sandcastle on the shore beside the sea. It will be washed aside by the next tide of intense feelings flooding her mind.

Likewise, it is futile to keep trying to convince her that you truly love her. Although she may believe you for a day or two, she will start doubting your love as soon as her feelings change. The result is that a pwBPD typically will frequently administer shit tests to test whether you seem to love her TODAY.

I really have no idea what to do. Being nice doesn't work.

Again, I suggest you see a psychologist -- for a visit or two all by yourself -- to obtain a candid professional opinion on what you're dealing with. Whenever strong BPD warning signs are appearing, it is important to see your own psychologist, i.e., one who has not treated or seen your GF.

In that way, Craig, you're ensured that the psychologist is ethically bound to protect YOUR best interests, not hers. I mention this because therapists generally are loath to tell a high-functioning pwBPD the name of her disorder. They often decide that it is not in her best interests to be told.

Of course, learning to spot BPD warning signs will not enable you to diagnose her issues. Although strong BPD symptoms are easy to spot, only a professional can determine whether they are so severe and persistent as to constitute a full-blown disorder.

Yet, like learning warning signs for a stroke or heart attack, learning those for BPD may help you avoid a very painful situation -- e.g., remaining in a hurtful relationship or running into the arms of another woman just like her. Learning the red flags also can help you decide when professional guidance is needed.

I therefore suggest you take a quick look at my list of 18 BPD Warning Signs to see if most sound very familiar. If so and you have questions, Craig, I would be glad to discuss them with you.