hi hattrick.
Do BPD's have moments of clarity? Like, times when they actually think normally and realize they screwed up ditching the non.
some pwBPD are well aware of themselves and the consequences of their actions, and some are oblivious. my w on exactly one occasion said "i don't forget, i don't forgive, and maybe that's just the way i am." that's the extent of her clarity. that this pattern of reactions might have victimized another person (me) was nowhere in her thinking. i am 100% convinced that her therapist hasn't told her about BPD and may not even know she has it, a thing both my therapists spotted without any trouble at all. as for "i made a mistake by leaving my perfectly stable relationship with my perfectly decent SO," my w did reveal some of her thinking (beyond what i just mentioned), and no, she hasn't that kind of clarity.
as a pwBPD married to an only child of emotionally incompetent parents who learned to fend for himself in every way and assumed that others could too, my w was never going to get from me the level of support and release from responsibility that she needed. so from her point of view she may not have screwed up. when i served her, she accepted and responded. not a peep of hesitation, in fact she's wanted to push the divorce faster. is she guiltily running away from the wreckage she caused? that could be, it's the kind of thing she does, but i'm just going to believe that she got sick of being with me and wants out for good.