Welcome.
This is understandably an emotionally fraught subject. To add to the situation, there is no one size fits all answer. There is also readings on boundaries here in the forum drop down list above. Here is some suggested reading on other post similar to yours:
https://bpdfamily.com/message_board/index.php?topic=320496.0Your first step is already done- she is not living with you..
In my own situation, things rapidly spiraled to my adult son getting violent with me due to his mental issues compounded by drug use .
Sometimes you have to give a strict boundary. Mine was, he had to see a therapist and get treatment by_____ date or I would start eviction procedures ( he was living with me at the time).
one suggestion is giving your daughter time lines like this. It can be cold turkey all at once, or little by little. Once he was out of the house the first few things I cut off was his gym membership, access to streaming services. A month or so later I cut out paying his credit cards( the statements showed he was spending money on booze). Lastly , 4 months later I cut off his car insurance payments. I got word to him through his other relatives that this would be taking place - 6 weeks notice).
The trouble is having enough stamina to hang tough and stick to the boundary as she will not take kindly to the boundary. You also have to know you are entitled to retire and to have money for you to live. The big question we all have is will this kick them into a free fall downward? This will not be easy. I can't really compare my case to yours because drugs have been involved in addition to my son having a other mental illnesses besides BPD. Others will chime in on their experiences , I'm sure. On the flip side, the ill BPD adult child could be made aware of the reality of the situation and get help.
