Growing up with even one parent with a personality disorder can be debilitating, but having two NPD parents!

I only had one, but what I didn’t learn were certain life skills that I had to later pick up in adulthood. And like you, I chose to be in a relationship with a BPD partner, actually I married two. Fortunately the second one is far better than the first!
I think we gravitate to what seems familiar. Like you, I was a target of criticism in my family. And probably for that reason, I didn’t seem to be aware of when criticism began creeping into my relationships, and then in the first marriage, turned into abuse.
I was accustomed to examining my faults, having had plenty of what my mother called *constructive criticism* (which I referred to as *destructive criticism*). The upside of so much experience with that is having grown a thick skin and now if someone criticizes me, I ponder whether it’s true or not. More recently, I’ve started to notice that a lot of those criticisms now appear to be projection, but that’s another topic.
You don’t need to immediately make any decisions. Trust the therapy process, assuming you feel comfortable with your therapist and it’s a good match. Participating in therapy will help you to grow some of those parts of your self that were un-nurtured in your family and will give you the strength and self assurance you need to make the best decisions for yourself.