So I finally found the song. It's "You & I" and Michael Buble performed it just softly and heart-killingly.
It's the song that I want to be the theme for our Christmas nite this year after a nice dinner with 'sauna chicken' or 'drunken beef' made-by-me, after watching maybe 'The Holiday' or ' Loev Actually' and snuggling on sofa. We shall dance quietly and closely till the world around seems to disappear.
It's how I loev on a Christmas Eve.