I have a close friend who is in a relationship with an ex-heroin user. There were many parallels in our experiences of our partners - the pwBPD is similar to someone who has been addicted to a powerful drug in their need to escape their own reality. That's what I inevitably thought whenever we would do our co-counseling sessions, as we called them.
At some point, I realised that I too was "addicted" to my pwBPD in some way. Then both my friend and her partner shared techniques on how to break an addiction.

Yes, many parallels all over the place. Cold turkey and withdrawal are one thing, but the digging out of the reasons - phew, big job. Doable though.