But I stymied as to how to work on a marriage when I'm the only one involved, and our only communication is email in which he threatens me.
I will continue the hijack. Read DB and DR. MWD says one person can work on a marriage. By working on yourself. By loving from a distance, Holding the door open so when your spouse is ready, you will both be able to have a marriage.
I have been working on my marriage by myself for quite a while.
