Hmm...not too sure about the letter. I guess because in the letter you are giving him control over whether or not he moves back in and works on R. After you said:
"To be honest, right now I don't even know if I want to try. Maybe it's just better that it's over."
It seems to me you are very unsure of what you want to do and where you want this to go. The idea of getting your M back is intriguing and exciting......but maybe not what you want right now. I guess my advice would be to take a few days and really think about what you want before approaching XH.
As for the taxes, I think you are wise to stick to the divorce agreement.
~SE
I'm moving on...at last I can see...life has been patiently waiting for me.
Me-32 WAH-35 DD-11 DS-4 H left 11-03 Piecing- 12/04 WAH again- 03/07 Married 12 years Divorce final May 15, 2007