Hi BeatriceO,
I am sorry that you are experiencing this emotional rollercoaster, and I understand the pain and uncertainty that one is left with when a relationship cycles from breakup(or near break up) to back together. It wears on your self-esteem leaving you under resourced to think logically and rationally. I think KatieLou is right; that improving your own knowlege of this disorder and having the strength and self awareness to modify how you communicate and establish boundaries is paramount to building trust with someone who suffers from BPD and introduce more peace in your life. I am currently in a breakup/makeup cycle right now for the last 3 weeks and it is deteriorating fast so I can sympathize with how you might be feeling.
A peice of advice/suggestion to think about perhaps: "Treat the person, not the disorder" It is much easier to be kind to a person that it is to the ailment that is driving the problem. Learn to position youself beside them emotionally when they are directing their ire towards you so you can look at the situation more objectively and not take the full blast of the other persons emotions. It will allow you to be more empathetic as opposed to sympathetic (ideally)
Good luck and all the best (and well done for reaching out for support!)
