Toasted cheese and bedtime

When should you go to bed?  Being tired is clearly an important criterion, but what happens if you are exhausted and ready for bed and your partner isn't?  That happens to us all of the time.  Should I make an effort to stay up and watch 'CSI' on late-night tv (always my wife's preferred choice), or attempt to seduce her into joining me in bed for some nooky?  Or should I simply go to bed alone (which often happens ... sigh!) and listen to the radio or read a book?  Generally I am in bed half an hour, sometimes an hour or more before her.  Usually I'm asleep by the time she comes to bed and so our opportunity for conversation, cuddles or coition is limited.  Is this necessarily a bad thing?  Do I sleep too much?  People say that sleeping for too long is bad for your health and reduces your life expectancy, although I have never quite understood why.  Experts confuse the matter by then saying that everyone is different.  It certainly reduces the amount of time available for other things - reading, listening to music, watching dvds and tv.  So when should you go to bed?  And why is eating toasted cheese immediately beforehand such a heinous crime against the digestive system?