We have been dating for a year. She has a blow up every week or two, sometimes an overreaction to something Ive done, sometimes I dont understand what shes upset about. She yells abuse, doesnt want to see me anymore then, a day or two later we are a happy couple again. Ive learned to be nonconfrontational, and try to just wait it out, but its hard. Trying to use SET (Sympathy, Empathy, Truth) which seems to help. The abuse hurts, but I try to shrug it off. What I have the most problem with is the insecurity, just not knowing if we will be together from week to week.
In order to be present and helpful for someone with BPD, you have to find a way to compartmentalize that insecurity. I work on it every day and over a long period of time have gotten better at it. I've been where you are and improved, but I still struggle (just read my posts). The longer you nurture that insecurity, the worse they will get and the relationship will become untenable.
For me, I exercise regularly, play music, and meditate. At work, I have also started to limit my communications with her so I can focus solely on my job, which improves my performance and thus my confidence. I have constructed a whole life outside of my partner, because I/we cannot get everything we need from someone with BPD. Just know that the abuse often has
nothing to do with you. I've seen massive improvements in our relationship by learning ways to weather the anger and stay present in the moment, because it is often only minutes later that she has returned to "normal". Those with BPD live in the moment, so you have to learn to do that, as well.