You will be to blame for a long time...I was for the better part of 3 yrs!
As for what you wrote...he might not see it as a door ajar
From his perspective it might appear that you are telling him that he is unhappy inside...when he maybe in complete denial of that because he see's that as you still... The last comment may come across that you are the better person(which you are, but)...that you are being noble while he is being a scum to choose someone else...
While a normal reasoning person may understand what was intended remember you are dealing with a MLC male! Two strikes right there...if you really want him to know, let time pass, and then be very black and white..."As far as I am concerned, until one of us remarries, it is NEVER too late to rebuild a better life together."...but again, I would give it time otherwise it will start looking like pursuing to him.
I understand the need you have...but like I said, I waited till 3 days before the D was to be final (and that was a Sunday so Friday was the only day to stop it!) and even then, H retreated back into the tunnel after leaving court that day...causing me, several months later and no word from him, to re-file for D the second time!
It is complicated...take your time...you have a good 2 months to practice the new you!