It is very scary to try new responses to dramatic situations. Even if we know our standby response can make things worse in the short and long runs, trying anything new adds stress to an already stressful situation.
I've also found having your borderline partner around their parents is very challenging. Even non-borderline parents often have contributed to the BPD behaviors of their children, even if only through being enablers, often from having a variation of BPD themselves. So, my hat is off to you.
As far as staying strong - post on this board. I will state that having a place to write things down that is not a diary (my teenage diary was photocopied and mailed to relatives by my BPD dad, cant keep a "normal" journal since) that can be stolen, is a lifesaver. make sure you are using a name and online presence that is not tied to other accounts or easily identified if your W comes across it. You NEED a place to be open, honest, and get feedback from others who've been in similar shoes.
I recommend reading up on Extinction Bursts:
www.
https://bpdfamily.org/2010/10/partner-have-borderline-personality.htmlI know our spouses are not children, and I don't sue this analogy to denigrate them, but I think some of their coping skills got stuck at age two. Think about a toddler, a tired, cranky toddler, and how they behave when they need a nap. The tantrums escalate and then, finally, they pass out, nap, and then things are better when they wake.
Changing your behavior upsets the balance that your W (and her mom) is used to. If she is used to yelling and getting her way, she will try yelling louder if it stops working. Our calm or new responses can be very invalidating to them because they NEED us to mirror and share their emotions. And that is ok. They can freak out. They can escalate. If you can be steady and constant, just like you know you'd need to be with a tantrum-throwing child, it "should" peter out.
It's a process that will be ongoing for the rest of your life - BPD is always there, but you CAN find ways that work in your relationship to mitigate the drama and abuse.
As for your children - I'd find age-appropriate ways to explain to them that mommy sometimes gets really mad and may say things she won't remember later, and that when she is mad it is not their fault, and they are not responsible for her emotions. As a child of a BPD mother (and father) I cans ay kids often thin they need to help the disordered parent. They feel it's their job, their reason for existing. So ask your therapist maybe about ways to help the kids NOW.