Possible Clues:

• Join in marriage
• Give up the single life
• Do the rite thing?
• Take seriously?
• What to do in the "Chapel of Love"
• No longer a single day, in short
• You and I would be single no more after this day, in short
• After this day, you and I would not be single
• Night that 'Dynasty' aired for most of its run: Abbr.
• Joined a union