I think you have a great perspective on this. I think it is good you made some fuss about the plant, it let him know that you can still get mad without him having to try and push your buttons (if you know what I mean as that was what he was trying to do before).
I'm not so sure about asking him for help... I would go with his flow on this one. You could look at 'real apologies' maybe, if you want to go down that route.
That is great that he knows that he has to work on himself. It says to me that all that stuff he put you through the other day is because he is lashing out and hurting. It almost seems he is floundering and having a separation/ divorce will give him structure. I think you are doing right in not fighting that (and I also think on some level his anger is also to do with you not fighting so he is trying to provoke you). Those six months are a really good chance to DB. JMO.
