SP, the beautiful thing about this is very rarely is one action or one moment a marriage destroyer...
You can and will do whatever that moment brings... and we will be here to read about the results and provide support and feedback...
The worst for you might be the anticipation of what is about to happen... rather than dealing with the consequences of choices after the fact...
My opinion, a song is a bit much in a tense situation... sometimes it is recommended that perhaps a simple card with the words "Still worth remembering." or something like that is just as meaningful...