Welcome, Wulfe. Hopefully, you'll find what you need here.
A few months ago I noticed her behavior becoming more extreme. The blowups came more frequently, and periods of irritability starting to occur nearly all the time. When she eventually informed me that she had been reducing her Prozac and was about to stop it entirely, I was not surprised.
I'm guessing that would likely be it. Other things could be changes in the relationship or repeated triggers or other changes in life, including age. I read a study recently that linked estrogen and progesterone levels to increased BPD traits such that lower estrogen or lower progesterone and estrogen can ramp up traits. It focused more on the E/P crash that brings about PMS, but could possibly apply to estrogen production tapering off over time with age as well.
In my case, I've always noticed things can get really rough as PMS and BPD combine. It's also been a rough few months lately, which has coincided with a couple things... relationship bumps in the wake of an affair and a campaign of self-medication using a glass of red wine a night to lessen how harsh and heavy her period has always been (one of the signs I have seen she is progesterone deficient / estrogen dominant).
Red wine inhibits the conversion of testosterone into estrogen in women. There is debate over whether the female body ramps up other production of estrogen to compensate, but a going belief and what I think she is seeing is... the red wine helps because it lowers estrogen and estrogen (or more accurately lack of a progesterone balancing ratio) can cause the heavy bleeding and harsh cramps by building up the uterine wall more than should be during monthly cycles.
So, already low in progesterone and lowering her estrogen artificially with wine... and a study out there linking low estrogen (and progesterone) to increased BPD symptoms...
I see this as maybe an aggravating factor over the past few months. I'm trying to gently nudge her to switch to progesterone cream instead. If the problem is an imbalance between the two, adding progesterone would have the same effect on her periods as lowering estrogen, but without aggravating the BPD.
So... all this to say, there can seemingly be a lot of factors. Dropping off the prozac is probably a good bet and most likely, in your case, but be aware there can be others.
And life is not always miserable; she has a good side, and the lifestyle that we share is in many ways very appealing to me. But I can't stand the anger anymore. I am trying to adjust my own attitudes because I can't adjust her behavior. What else can I do?
We definitely get it! I think a lot of people here totally understand that there can be upsides to a BPD partner. On the flip, we also understand the effect of the anger.
Adjusting your own behaviors and attitudes are what these boards are mostly about... because of exactly what you are saying!