Barb,
Sometimes this happens but it doesn't mean that it will start all over again. You and him are not doomed. Six months ago my daughter got completely sober. Twice she fell, but got right back on the recovery horse. She never went back to her DOC but nevertheless it was a relapse. Please keep in mind that he has had a lot of clean time and he knows how good that feels. Have faith that he will catch this before it gets out of hand. You and he both know that he can do it because he did.
Stay strong and if you need to fall out of life for a day or two thats okay. It is a real disappointment.....I know. It seems that the whole time that they are doing well, we always waiting for the other shoe to drop. When it does it completely sucks the life out of us. It is not the end of the world.....he had a slip up. He sounds like a strong person.....you'll see.
Stay with us......we're all praying he bounces back quickly..........Lo