Some friends have hepled me to whiddle it down to this:

Wife,

This is not what I wished for our lives but you have left me no workable choice.

Contact me only regarding our children and only through email.
All other contact can be done through our Pastor.

I have good memories of the woman I married and I wish I knew where she went.

If you should decide to put some work into our marriage it is a possibility.

The door is closed but not locked.

Yet.

Husband.