Visiting Old Montreal is a must.
Enjoy some pastries in Little Italy. There's a good Italian restaurant across the street from the pastry shop. Can't remember the name, but I think it's in a corner spot. Little Italy is really little, so you can't miss it.
Visit Notre-Dame Basilica. You can take your honey on a horse-drawn carriage ride that starts across the street from the basilica. IIRC, they have a short tour and a long tour around town.
Other places to visit include St Joseph Oratory, the Biodome, Olympic Park, and don't forget to take a stroll down St. Catherine Street.
There was a good place for breakfast when I went there last time. It had "eggs" in the name, but I can't remember right now.
For a treat at night, have dessert at the Queen Elizabeth Hotel. It's a little expensive, but worth a one-time visit.