I wasn't really with my ex long enough to get too obsessive about finding where he was hiding booze (certainly realized that he was secretly drinking), but it's honestly kind of amazing how smart and stupid the hiding can be. Sometimes it would seem that my ex would all of sudden be slurring and I had absolutely no idea when and where he had been drinking. On the other hand, one time I literally saw him wrap a 20 oz beer can in his towel on the way to the shower. I confronted him about it, he lied, I said "ok, well then open up the towel" and sure enough there it was. He looked at it like he was so confused as to how it had got there...