I too would be livid to receive a non "emergency" phone call at work. What an immature childish ploy.
You are worried about him moving on? I am saying this without malice, but truly he is not a hot commodity. How many women are looking for an unemployed alcoholic to care for and screw up their life? I wouldn't wish that on anyone.
He may very well move on, but the next person, is going to live the same hell you have. If nothing changes, nothing changes.
You have been on a crazy rollercoaster, allow yourself to get off. I would stop supporting him, allow him to own his disease.
You deserve better. Start by being your own best friend. Do something special just for you. You are making such progress.
Trying to see into the future is robbing you of your today............ take care