Most Helpful Guy
It depends on how the letter is written. If it is constructive I'll accept it and actually it would be very touching since she went through all that trouble for little ol' me.
I would HATE if the letter is with a strong apologetic flavor - it means the writer is stuck in the past and thinks about "could have been this could have been that". I'm not telling how you should shape your life philosophy, but this is what a lot of people don't like, in general.
I also don't like that "if you'll be happier without me"... and so on. It's bordering on victimization.
My guess, your ex wouldn't give much of a reaction UNless he feels similarly about the situation.