I'm so sorry to hear things are moving so quickly for you in the direction you least wanted to go, 1313.
I have no idea if a letter is a good idea, or not, but your heart is surely in the right place. I hope someone else chips in their thoughts on that.
What I wanted to say is that I completely relate to your lack of anger. My therapist keeps saying "you must have a lot of anger at your husband for what he's done," but any anger just passes me right on by most of the time. I may feel it for a little bit, more in the last few days, but then it just goes away. I'm just really sad and missing him and confused.
H: 44, Me: 45 Married: 20 y Together: 25 y no kids Walk away: 12/15 Asked for temp separation 12/25/15 PA confirmed 3/16 (apparently neither the first, nor the last PA he has had) H filed for D 5/16