When you accept the fact that you cannot control HIS addiction, you let go of the illusion that all the checking, monitoring, questioning, peering into their eyes, etc. will change anything. You take the focus off the addict and put it back where it belongs: on you and your children. This is the beginning of detachment and it will restore you to sanity. As you continue taking care of yourself, what needs to be done next will become clear.
If you like to read, pick up Codependent No More by beattie. It changed my life.