Hi 4myluv,
Welcome to the boards

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I'm sorry to hear that your H seems to be stuck on the idea of being bipolar. I've seen this quite often though. Bipolar is easily acceptable as far as a diagnosis goes. It's talked about openly in public and a lot of people think it's just mood swings (although it actually has very different markers than just mood swings).
One thing I've found though is the diagnosis isn't as important as the relationship aspect of BPD. If you can begin working on new ways of communicating then that in turn can help your H begin to better. We have a lot of great workshops on the right side of the page that can help you begin to understand BPD and being in a relationship with someone with it, communication tools, and information on taking care of your own emotional health. Looking forward to learning more about you and your situation.