Hi Cyrus304,
I am trying a new approach today. Instead of getting defensive when she gets agitated, I will instead try to focus on what is causing the agitation. I will try to validate her feelings, but I also refuse to sit and argue.

Your change matters more than your think! Let's be clear you likely have not developed a good sense of what is really the issue and what to change but the very fact that you are willing to rock the status quo is cause for hope .
My wife has BPD, and our marriage is in a state of hell I have never experienced before. After last night, I was at my breaking point. The fights simply go round and round with no end. And no matter how logical or rational I felt I was being, I simply could make no head way.
I felt like no matter what I did, I could not win. It was never good enough, or if I did what she asked, suddenly there were "qualifications" that would invalidate the process. We had the same fights and arguments over and over, and they went from weekly, to daily, to almost hourly.
You can't win. The rules will be changed below your feet. It is disallowed to win. If you believe you are in a discussion you are mistaken. This is not a discussion but a theater for her emotions. Don't discount it - it has huge value for her and you can make it work for yourself. But don't take it for a rationale discussion - you are playing the wrong game - playing by the wrong rules - playing for the wrong stakes.
What I have read the past few hours (on multiple BPD sites) has made me rethink my approach to the matter. In the past, I heard what she was saying, and would argue it because what she was saying was not logical or factual. But now I'm reading to look past the words she uses, and instead focus on the feelings behind those words. In a sense, I now understand why she would always complain that I was not listening to her. I was, but I focused on what she said, not why she said it.
Active listening is a key skill. There is plenty of pent up stuff - mostly emotional but also other baggage - that hides behind illogical arguments. Teasing it out is a challenge and developing this skill takes focus, effort and time! The board can sometime a valuable resource to tease out meaning of odd remarks and behavior and even if not helps to think beyond the most obvious. We are all bind to a degree.
With all the active listening keep in mind that there is usually not something to fix for us. As odd as it sounds fixing is not needed. Understanding her but not taking ownership yourself. For a lot of us this requires a mindshift.
Anyway, I am hoping that I can connect with others in similar situations, and hopefully learn ways to deal with and hopefully overcome some of these problems and issues.

,
a0