How much wine is too much in a night?

[hotwine]

The quantity remaining after dinner is usually only one glass, which is half the lovely wife's allocation. I dutifully put it away for her to have the next evening before dinner (while I move on to the next bottle). Half the time, if she's not lookin', I'll go ahead and finish that sucker myself. But if she IS lookin', I'll catch some kind of grief: "Haven't you already had two glasses?" I'm using the biggest confounded glasses I can find already (Riedel Bord. Somms.).