AD, and welcome to the family! We are sorry for what brought you here but happy that you found us.
Do feel free to tell us more about what is going on. Has she been diagnosed? Is she in therapy? Are you? I ask because these things help to support the success of a relationship.
One thing that has struck me deeply recently is how much power partners of pwBPD have. When they escalate, we can make it worse or better by our actions. It is quite a thing to realize that you can set a person off and destroy their entire day by how you respond to a dysregulation. Or you can support them to self-soothe.
The bottom line is that you can change. Not because there is anything wrong with you - her voice telling you you have no worth only impacts as far as you believe it, and why believe a pwBPD? But there are certain ways partners can behave which are pretty guaranteed to make things worse.
Here is a thread that can assist you to think through these things:
https://bpdfamily.com/message_board/index.php?topic=66672.0