This article might be helpful:
https://bpdfamily.com/content/how-to-get-borderline-into-therapyIt’s often really difficult to get someone with BPD into therapy. Often they think their issues are due to other people, not themselves. And not wanting to look within is a problem for them because typically they have so much internal shame and self loathing.
It’s good that you’re doing therapy. That, and reading here, will really help make things less volatile in your relationship.