Its tough ... I know... we all struggle with it, seems if its easy to detach then one was not quite attached in the first place and they most likely would not be here, would be filing and waiting for the D day to come .. totally get it.
Here is where the meat and potatoes are, its time to work on you. You just stated: "I will file away the not being negative and just letting him talk for future and in meantime I will not contact him and will get on with my GAL!"
I took 2 things from this... #1 the negativity, yup .. lose that and replace it with PMA, no spouse wants to go back to Mr or Mrs Grumpalupagus .... and better yet if you are out and about doing your own thing and can actually be happy (fake it till you make it up to this point) This makes the WAS stop and think, maybe even be confused .. THIS is a good thing, flips the table, now he is wondering ... what did I do? Whe is SHE happy all the sudden. Classic Bait and switch.
#2 the Contact, yeah we call it going Dim/Dark .. very useful tool, not out of punishment but because you are so darned busy and having such a good time, you really are not locked into being available ... this tool was important for me and turning things around, drove W nuts when I was 'distant'
Another thing ... you touched on it, and this helped me over the detachment hump. I became VERY religious through all this, it just happened. Giving it to God, was the best move I could have possibly made. Had my wishes and wants been granted when I wanted them, things would not have worked out, I needed time to change ... as did my W. Use this time to become a better choice, as the book states .. a person only a fool would leave.