Lost the bet

It seems I lost the bet. That was exactly what I was hoping for. I bet my son that he couldn't abstain from alcoholic drinks for one month. The bet was discussed some time ago, at first he said it was easy, but I pressed the issue. Finally he agreed - perhaps it was the stake. The month is over, I have received a text saying he was enjoying his first drink after his time of abstention. I have trusted him to do this of course. I could not be with him all the time, or check up on him everywhere he went.