I suppose I could be really obvious and dense and suggest Romeo and Juliet by Dire Straits and also Sergei Prokofiev's ballet/orchestral suites of Romeo and Juliet.

Otherwise, I suppose I could suggest some general songs about love. Without You by Harry Nilsson might be one, referring specifically to the ending. And I suppose, because it just happens to have come on WinAmp as I'm typing this, Girl Like You by Edwyn Collins might work for when they first meet. I'm terrible at this sort of thing though xD