Hi conflicted55, thanks for the details.
Whe a person with BPD splits, are they consciously aware they have split? or could this be unconscious? My SO does not seem to recall conversations she had when she splits.
The splitting seems to be one of your big focus points in your relationship. My belief (theory) for people with BPD is that they either alter their memories or selectively forget to shield themselves from the consequences of their disordered behavior. Did you ever see that TV show The Affair where they show events from two different characters perspectives and sometimes what they say or did is completely different? I think its like that. In reality she slung a bunch of curse words and slapped you in the face, but in her view she just said "you're so annoying!" and threw a dishtowel at you.
I think the key goal in dealing with splitting is not so much trying to understand it but rather how to not let it affect your own sanity. Keeping a record of disordered behavior would be helpful to maintain your perspective on the situation as well as prepare you for the next splitting episode.
I have entered therapy and my therapist is confused by my partners behaviour.
Have you brought up the possibility of BPD with them? If yes what did they say?
~ROE