This depends...I am not sure, but I can share my experiences. My AH claimed to be recovered for many years. I often would suspect he was drunk at times of the day or places where I thought that was an impossibility. Not slurring speech or falling over, but he looked it...just unable to completely maintain. Come to find out, he was drinking alcohol that doesn't leave an odor, and would sleep most of it off or sober up before I arrived or whatever.
Does your wife have any therapy or recovery she is in? I am not sure about others, but from my experience I have not seen anyone who maintained long term soberity without some kind of help.
Hope this helps. However, I seem to think that whatever your gut is telling you, might be the truth. It was in my case, even though I thought "impossible" and was told that I am being "crazy"...