Hi HawkRidge,
I related to it as I saw the behaviors I did when my relationship with my ex pwBPD was crumbling. One sign that spoke to me was that the insecure partner (that was me) would post overly optimistic or complimentary posts on Falsebook. I did that all the time towards the end. "i am so gratefuk to be in such a relationship." Inside, I think I was trying to convince myself and my ex that things were better than they were and, perhaps, I was hoping it would make the relationship. Go back to the idealization phase.
It sounds like you're describing denial or maybe rationalization. I think that it's common that we hope that our pwBPD return to a permanent idealization phase. Did you understand the complexities of a PD and the mirroring in the onset of the r/s?
Granted, there's mirroring in the honeymoon phase at the onset of a relationship regardless if a person is disordered or non-disordered, I think some differences would be that a pwBPD lack a stable sense of self and mirror others because they have an unstable self image, don't know who they are give up complete control in the idealization phase to attach to a partner and when their part time false sense fails in the r/s they switch up the control.
You seem like a sensible man, were you trying to make things work for the sake of the relationship and trying different things or were there also things under the surface, complexities of the disorder, things that we may not understand going in to the relationship.
A personality disorder is a difficult thing to detect, I'm not a trained professional, I'm speaking for myself when I say this but I had to put the pieces together after the r/s broke. I thought that the person that idealized me was authentic and I had thought that she was going through something and held on to the hopes that the person that I met would return, I thought that she would snap out of it.