On the topic of what predisposes someone to continuing a relationship with a pwBPD? I think anyone can be attracted to a pwBPD but not all relationships progress long term.
Being willing to appease and having poor boundaries is one aspect. FOO dynamics can influence this. My FOO was similar to Pook's in that, we saw things our mothers did that were wrong by our own values but we were not allowed to stand up for them, or speak of them. We were taught, from an early age, that our boundaries mattered less, for the sake of family harmony. What was "right" for our fathers may have taught us to abandon our own values and not have boundaries in relationships. Kids don't have the nuanced understanding of this decision like an adult would.
I saw some recent videos that discussed the adult parentified child in relationships and how we tend to dismiss our own feelings and regulate other people's feelings. We may end up in relationships with people who have poor emotional regulation skills. The relationships persist because we do the regulation for them. They gain a sense of comfort but it also keeps them from dealing with their own emotions and possibly learning better emotional regulation skills. If the parenfied partner then expresses their needs, these needs are dismissed, the partner can't meet them, and if they don't regulate their partners, the partners can then blow up in anger, or react in other ways.
The term BPD isn't ever used as it's not the only situation where someone has poor emotional regulation skills. However pwBPD have poor regulation skills and so the pairing between them and an adult parentified child may be more likely to progress.
People with autism also may not have strong emotional regulation skills for other reasons. They may be overwhelmed and react. So I think the pairing of BPD and autism may not be as frequent. I have also read that a NPD-BPD pair can be unstable.


