I almost hate the "perfectly normal" part more than the alcoholic mess part. You know the other shoe will drop eventually and then you're stuck worrying about "when". My fiance's parents met my AM when she was having a "perfectly normal" day - they were shocked when my fiance told them I had no contact with her and took quite a bit of history before they understood that she wasn't quite as charming as she had let on.
Frustrating.