Notice when it happens. What is going on at that time? What fear(s) drive(s) the pushing away?

I think it originates in our original attachments. I am reading a book that says that certain attachments/interractions with the primary caregiver are seen in a great majority of those who go on to become borderline. "Attachment in Psychotherapy" by David J Wallin.
My T talks about attachment, refering to Anxious Attachment often.
How we develop affects who we become.