Gosh, CC43, you've nailed it. 100%. I agree with all you've written, and I sympathize with your husband being the punching bag as I am. It's the hardest thing I've experienced, and I wonder if he would say the same. We are not wired or prepared to parent that. It sounds like you are both wonderful parents to her and very patient.
I had another child with struggles, but for whatever reason, they never blamed me or raged at me, so I was able to stay empathetic and involved, and we are close now.
If a friend told me her child was acting like mine to her, I would advise her to set limits and stop taking calls or responding to mean texts. What holds me back is thinking of her alone, feeling unloved and left behind. We won't have much of a relationship if I wait for regulated communication. But if I don't wait for that, I continue a pattern of escalated, rages that has been happening for years.
So either 1) I take the verbal blaming and rudeness in every call and text to maintain connection, or 2) I don't take the calls per my limits, and she receives it as silent treatment and abandonment.
I'm so glad your SD did receive treatment and that she's using some of the skills at times, and showing stability. That's amazing! My oldest did DBT and had a wonderful therapist. At the time, she didn't use the skills much, but she uses them now!



) Too busy, Too happy etc etc.
Splitting: Protecting Yourself While Divorcing Someone with Borderline or Narcissistic Personality Disorder