I am in a similar sitch. I am too straddling the two worlds of saving the marriage and just moving on.
Prayer, and forcing a positive attitude work for me. When you start to feel the hoplessness go to a happy place. Put up the STOP sign in your mind and direct your energy elsewhere. You have to force yourself, have discipline.
I know easier said than done.
Somebody told me just to settle my mind, keep busy.
You have to know, that no matter what happens, you will be ok.