The song was reaching its end, providing a musical background to the small world he was in with Emmeline - a peaceful happy world. While not necessary, it helped with the mood. And it still felt, in a way, like they were dancing.
He took a moment to think about when the last time he danced had been - years, back in...1995. That had taken effort, which for his memory, was saying a lot. His hand found a strong position on her back, and when the song ended, Kingsley dipped her down, holding her steady, "It's my honor, Em, and makes me quite happy."