Thanks for writing about this. I have quiet BPD and it went undiagnosed/misdiagnosed for years since I didn't display violent or chaotic traits. Meanwhile, my relationships were in shambles and I never understood why.
Romantic relationships in particular are still a struggle, but my life has started to feel much more manageable since doing a lot of personal work around boundary-setting, understanding past relationship problems, etc.
Understanding that quiet BPD in particular often emerges from severe trauma--in my case, childhood SA and neglect--is key for treatment.
I also appreciate you normalizing this misunderstood and much-maligned disorder. I've never abused anyone, deliberately violated anyone, rarely engaged in bullying, and have overall tried hard to be a good person despite emerging from horrible circumstances, yet because my personality is chaotic and I have poor boundaries, others have consistently taken advantage of me and I have not pushed back effectively..and I have brought the resulting hostility, terror, panic, and trauma into my relationships with even well-meaning people.
In my opinion, the best way to understand the psychology of someone like me is to see me as someone who has been essentially tortured or endured some other decades-long, unrelenting physical and psychological trauma.