That's a really tough situation. It feels like no one in the world understands. But then how could they? Someone who's never experienced depression or BPD can no more understand it than a colorblind person could understand red and green by reading about colorblindness in a book.

It sounds to me like he needs to be reminded that it's not "all about him." But that's difficult for people in our situation to explain (I stopped trying because it usually just made things worse). What helped my wife understand was face time with a professional (in my case, a pdoc and an experienced ECT nurse). The same message coming from a disinterested professional is completely different than hearing it from a spouse.

In my case the "explainers" were mental health pros, but I don't think that's strictly necessary. Anyone who understands your situation, and whose opinion your husband respects (and can discuss it calmly and with tact) would do, I think. If nothing else, this person might be able to persuade your husband to talk to an MH professional.

This is huge in my opinion. I feel the same about my wife & kids, and I tell her that as often as I can, though never enough. Face to face is often difficult, but texts, voice mail, sticky notes...