You at least have a realistic expectation on this, what you are experiencing is normal. The hurt and pain that this causes you can only be addressed by learning how to not let it effect you rather than by hoping he will get better.
Yes a pwBPD will go for your weak spot, you will rarely be immune to that but you can learn how to not let it cut as deep nor last as long. most importantly is to learn not to react,m as that leads to counter reaction and escalation, thereby a means he can projict hostilities onto you and it being your fault. As you become embroiled in conflict which has nothing to do with the original issue. Resentment builds in you, and it becomes a validating means of self soothing for him, and nothing gets better.
Things can get better, even without the mechanics of BPD thinking being removed. It is a slow and evolving process. Watch very closely the dynamics of reaction and counter reaction. Whereby his problem suddenly becomes both your problems, to the point you are afraid to raise anything. It is OK to raise issues, and your version of reality, where you come unstuck is if you try to sell your version. If you dont not raise your version you will feel cheated, and when it finally comes out then withholding it will be seen by him as betrayal, and it all becomes magnified.
And truly this relationship has strengthened and reinforced my own emotional health and growth.
Do not underestimate this bit, it will make you a better person. Think of your therapy sessions as being part of this and not just as a required chore to help someone else.
