After some sleep and thinking - I decided to write him an apology email.
Thing is, the guy has been solid from day 1. But me? With my borderline personality, plus the suicide of my fiance just 4 months earlier, plus all my baggage - I put him through a lot of pain. The worst he's done to me is not email or call for a few weeks. I've done much worse to him.
I didn't write the apology email to "win" him back. Instead, I wrote it because I honestly feel remorseful and want to let him know that, although I openly blamed him for my unhappiness, he didn't cause any of it. I asked for his forgiveness, and explained that I was in such a bad mental state that I didn't know I was being hurtful towards him.
I know I did the right thing. I am at peace with it.
Now I can spend this week, while he's away, trying to figure what to do next. Maybe a true separation is the way to go.