DEAR MISS MANNERS: My husband is an early bird and goes to bed every night at 9. His nighttime routine starts at 8. I would like to invite a couple we sometimes dine out with over for dinner. Can we issue the invitation from 5:30 to 8? Or would it be better if we didn’t state an end time, and my husband just excused himself at 8? GENTLE READER: So you were being literal when you said your husband goes to bed at 9 every night, whatever the circumstances. It occurs to Miss Manners that your guests might see changing one’s regular routine to enjoy the pleasure of their company as a relatively min…