Where you mention the Dr. says she doesn't really have bipolar, but borderline, I can't help but think he is simply using the BP NOS code for insurance purposes. It is regrettably common. It's about what insurance will cover. Really, there are two reasons this happens, the other being that many people with borderline don't react well to being diagnosed with it (as you have discovered, and this is why she accuses you of psychoanalyzing her even just bringing it up). It is a highly stigmatized dx. Your wife's reaction to your talking about it pretty much confirms reason number two. I personally would guess it is both factors.
While I don't have any real reason to believe that you are psychoanalyzing her, I would advise laying off the borderline stuff, because it won't go well. Actually, I'd advise not getting into any of it (bringing up the borderline or playing along with calling it bipolar). Has the Dr. advised you to be involved? It's very tricky territory to navigate.
I do understand that it's frustrating.
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Makes me sick to the heart, Oh I feel so tired. And the way the rain comes down hard, that's how I feel inside.
--The Cure