There's been a lot of nice songs suggested. For the older set that I usually play for these songs are always a hit. You know you've made the connection when your audience is singing along.

For Valentines groups I like to play lots of "Girl" songs. Here's some of them.

Margie
The girl that I marry
Easter bonnet
Let me call you sweetheart
Daisy Daisy give me your answer true
Girl of my Dreams
Red roses for a blue lady
Love me tender
Georgia on my mind
Girl from Ipanema
Bird in a gilded cage
Dearie do you remember when
I don’t know why I love you like I do
Paper doll
Peg of my heart
Sleepy time gal
Sweet Georgia Brown
Sweetheart Tree
Tennessee Waltz

Have fun!