Havent much advice to give but wanted to say sounds like you're doing great. Detaching is hard, not wondering ehat theyre doing all the time is hard, but I think in time we will be able to go through a day without thinking of them. .
Like you, I have no intention to date. Cant see myself doing it for a long time. And like you mine wasnt dating when he left. Just depressed and angry. But then they realise they are alone - so to fill that space they date. I am not saying yours will stay dating, im just saying that if he did, it would be because he feels so alone.