Leslie, I know this is a really difficult time for you. I've had my W "end it" with the OM twice now, only to go back to him each time.
If you don't mind my saying so, I think you should try to find more fun or rewarding things for you to do away from him right now. Don't stop focusing on GAL. When my W came back each of those times, I think I was so focused on "helping her" with her "mourning" the OM, that I smothered her and chased her back to him.
Spending more time away from your H right now will also help you detach. Good luck.
The LORD is near to all who call on him, to all who call on him in truth." (Psalm 145:18)