Hi Cat and welcome to the family! Great question and I'm really glad you found us.
BPD is a mental health condition that affects close relationships. That tells me that your sister considers you a part of her inner circle, someone she relies on to talk, rant, or whatever. That's what close friends do, after all. But it sounds like your sister is taking that to another level and focusing mostly on herself...not so much on you. It's a very common problem with a BPD loved one and almost every member can relate.
For me, I have a BPD daughter that I had to distance from. Not because I don't love her or want to talk to her, but it was important for me to get outside of that "inner circle" with the constant daily updates. Her boss was mean to her, there's something wrong with her dog, the neighbor is a jerk, this new person they just met is the most amazing person on Earth. It was endless and like you, I just couldn't do it anymore. Everyone was either a saint or a demon...there was no middle ground.
So I slowly backed off, strategically. I'd intentionally take 10-15 minutes to reply to a "rant text", and maybe an hour or two for more general stuff. If she was in crisis, I replied quickly, but otherwise I gave her enough time to text someone else and rant to them instead.
There were many bumbs in the road in this process and currently, I'm told my daughter is back to hating me. That's okay though, I understand what that means and I don't let it bother me anymore. I'd rather have her bad-mouth me from time to time than be in her closest inner circle. Like you, I just couldn't take it anymore and it caused a lot of anxiety.
I also know it's not real hate anyway. My daughter told me ex wife recently that we had talked. My ex was surprised because she thought we didn't talk at all anymore, like something serious happened. Maybe it did by my kid's version of events, I don't know. But every time I talk to my daughter, she seems to tell the entire family about our entire conversations. So that's not someone who actually hates me, she just misses her dad (and unintentionally abusing her dad).
You have to make a choice- no matter what you do, you'll get some pushback and blame. You can block your sister, or be much slower in repliyng, or keep having the same conversations. But from my experience, it's much easier to be a distant relationship and not in the middle of everything. I hope that helps.


