Just the facts, M'am
Disagreements and misunderstandings happen. But when someone keeps wanting to make you wrong, and ya get the feeling you're going round and round the Mulberry Bush with 'em, it's because they feel empty and dead inside, without the stimulation that conflict reliably provides.
Borderlines love a good argument. They'll look for the 'fly in the ointment' in your dyad, because they literally THRIVE on chaos, drama and conflictual interplay. This feels enlivening for 'em~ so anger and disappointment are perfect catalysts to project their own shortcomings, failings and flaws onto You.
Smart people bail, as soon as a relationship starts to feel toxic. When an emotionally undercooked person cannot look into their own mirror and see the cracks therein, they (sadly) cannot see or comprehend why people who supposedly matter to 'em keep retreating, or disappearing from their life.
People with BPD traits are EASY to love. This is why we fail to recognize how messed up they are, until their devaluing and diminishing behaviors toward us start to emerge. It's hard letting go of someone we once cared a great deal about, but they will continue depleting your energy and eroding your trust in 'em, until you stop giving them the attention they so desperately crave and seek.
Always remember, when it comes to exchanges with another that begin to feel emotionally demanding, energy draining and toxic, the BEST response is NO response.