He said "Heather, I said I don't want to talk about this right now." I said...

Sometimes, when a guy doesn't want to talk about whatever problem, he withdraws. Simple as that, and any pursuing him isn't going to be fruitful. See if his demeanor changes in two or three days.

On the other hand, given that your interpersonal dynamics are way off the scale, I wouldn't think not having said "bye" was the most important aspect of that conversation.

There is no respect in my R anymore. I've been so preoccupied trying to figure out why and how and blaming myself or blaming H, but the bottom line is that I guess it doesn't matter WHY. At this point, things have gotten so severe that WHY doesn't matter, it just IS.

That's a good starting point. Now the thought is, what changes are needed in behaviors so that both partners feel respected? But underlying that is the fact that both partners have to want to achieve that outcome. Perhaps address that matter directly, openly, calmly and honestly?