Hi mssalty ,
For a person with BPD, if their partner brings up frustrations, they will find the worst possible interpretation of it, such as interpreting it all as a criticism and possible rejection. But why? The reason why they interpret things like that is because this interpretation is the one that elicits the biggest conflict (at least in their head).
They will say they want you to apologize, but unconsciously they just want you to engage in the fight. This is why they make things so frustrating for you, so that you lose your grip and explode as well.
But why on earth would someone want something so defeating and harmful for the relationship? Because they need the endorphin reward they get from the conflict, and this is of primal importance for them to regulate their brain [**]. Unfortunately, when doing so, they are so involved in the conflict that they don't even remember it will push their partner away.
But as Pook075 explained, if you love this person, then there might be another way around because:
"They just want to feel loved and supported in every interaction. They want to feel like they matter and they're seen."
That works so well because feeling loved releases endorphins and also activates many other neurocircuits in the brain. Therefore, it replaces the need for conflict. Have you ever tried to disarm your SO using this approach?
[**] see the EOS theory on BPD:
https://psycnet.apa.org/buy/2010-06891-012