I don't know your W and don't know how she would take this, but if it was me, I would make a point of keeping track of how much she sleeps for a couple of weeks (maybe more). Then I would spring it on her. I would approach her with FACTS and tell her that I was concerned about how much she sleeps. Tell her that I know that different people require different amounts of sleep, but that I thought her sleeping so much was out of the ordinary. I would couch it in health terms rather than complaining that she won't ML because she's always asleep. Seriously, excessive sleepiness or tiredness can be a sign of physical problems as well as depression, e.g. elevated blood sugar levels (diabetes) can cause sleepiness and lethargy. Don't even mention sex, just her health and well being.
