Hi BT400 and
This
is tough. These are the hardest relationships, and people who have families without PD dynamics sometimes don't get it.
Like you found, intuitive relational moves ("just be nicer") don't always make things better when BPD is involved. Sometimes it can take more strategic thinking plus
new tools, skills, and approaches, to get things "okay enough".
What kind of support do you have for yourself right now? Individual therapist, clergy person, family, friends?
While (as far as I can tell) my husband's teen kids don't have BPD, their mom has many traits, and she remarried to a guy with many NPD traits, so it's in the family system. My H and I have needed a marriage counselor for ourselves, and I have an individual counselor, even though neither of us have a PD -- it's that difficult to cope with. I get it.
I've also signed up for the
NEABPD's reputable Family Connections program, which is a free 8-12 week online program for family members of loved ones with BPD. My understanding of the program is that the leaders also have family members with BPD, so they have lived what you're living. There is a strong focus on current research, evidence based approaches, your own learning and skills improvement, and self care. Take a look -- could be a good fit.
...
Do you and her mom have any kind of cooperation/communication at this point? Are there any areas of coparenting where conflict is lower (transportation, attending school meetings, etc)? We are currently at zero communication with H's kids' mom right now, so I get it.