This is an interesting comparison, Reclaiming. In fact, many members here have noticed how addiction like a BPD relationships can be, and how much leaving one is like withdrawal. I don't think it's a perfect analogy, personally, but it's not too bad either. There are very real biochemical pathways activated in our brain when we fall in love, and these are powerful forces to maintain our attraction and connection to the person we love. Losing these has been shown to be very similar to physical pain. There's
an interesting article on the site about the biological effects of breaking up. Maybe you might find it interesting.
A little aside, it's interesting too how you describe the fear of being lost in a confusing and unfamiliar crowd. This is how I've heard having BPD described in
Stop Walking on Eggshells: being a small child all alone and lost in a crowd of unfamiliar, frightening faces desperately looking for your mother. Maybe your insight can also help us to understand something of how our exes feel.