Nice suggestions. I know some of them.
Roseville Fair is perfect, as is When You and I Were Young, Maggie.

I'm kind of surprised that there aren't more. There are a lot of married people and they can really use a romantic song every once in a while. If they're lucky, more often than that. I love my wife and I'd like to express my love musicaly but all the good songs are written for the courted or the jilted.