Starcrossed, one of the effects of alcoholism in the early stages is related to tolerance for alcohol. To quote a section from Under the Influence that stuck with me: "Alcoholics typically experience a dramatic climb in tolerance in the first stage of alcoholism and can often drink huge amounts of alcohol without showing obvious impairment of their ability to walk, talk, think, and react. Anyone who observes the early- and middle-stage alcoholic's drinking behavior is familiar with the fact that the typical alcoholic can drink as much as a liter of wine, a dozen beers, or even a bottle of whiskey without acting drunk."
It was astoundingly true with my AH. As was the fact that my AH would consistently lie about whether he'd had anything to drink or how much he had to drink.
Trust yourself. I'd personally trust a breathalyzer before I'd trust my AH to tell the truth about drinking.