The letter is not bad but the list of things that she needs to do at the end I would leave out. I gave my W a similar list and it only drove her further away. If I was to to it again I would leave it up to her to figureout how she can rebuild the trust between us. Try something like this instead of the list.
"For us to rebuild our marriage trust needs to be rebuilt between the two of us. I am unsure how we go about rebuilding trust, but, we both need to make the effort to rebuild the trust that nolonger is there."
If and when she recommits and comes to you asking what she can do then make a suggetion off of your list. Otherwise I think it comes across as controling and pushes them away.
