I've literally just been cured of BPD and you've nailed it so succinctly here that I hope you start giving lectures to other therapists. I was abandoned over and over and over again in my youth. Of course I was terrified of it!
It took finding a man who loved me enough (even after I divorced him) to remain committed to the love he had for me for me to begin to heal. I've now opened myself to him in ways I never thought possible. I've become vulnerable with him even when it required pushing the boundaries of my greatest fears.
I was never able to feel safe enough with a therapist to even come close to the work I've done with my partner, who took time to prove time and time again that I was safe in his care.
I've written some about my journey if you're interested.