Hi half-life
Yes, there's a variety of stories and corresponding emotional states on the board here.
I think it's a good thing that you consider your wellbeing a priority in your decision making with your partner. Yes, each of us have feelings and they belong to the person feeling them.
It may feel that there's not specific milestone. Yes, it is an ongoing process of growth. Hopefully that growth can be described as positive development. I'm glad you shared that you took away those valuable skills from your experience with the pwBPD. Me too, I've felt that I want to put more effort into a healthy relationship after this kind of assessment.
You can consider the steps on the right as forms of milestones. If you can readily perform what's in those stages, I think you can say you've touched the milestone.
I look forward to seeing more of your thoughts on your growth from here. I encourage you to explore the board that covers personal inventory:
https://bpdfamily.com/message_board/index.php?board=27.0There are some interesting personal diagnostics on that board if you'd like to do some measuring.
I hope you maintain your peace.