Well, Slick, I don't call this a tragedy. It is simply the bittersweet end of life that we all must face. We know that Aragorn was a mortal man and Arwen chose to become mortal, and we are supposed to think that we are actually reading a forgotten history of long ago; so JRRT is simply filling us in on how their lives ended. "They lived happily ever after to the end of their days."
But Arwen became as a mortal woman, and yet it was not her lot to die until all that she had gained was lost."They lived happily ever after to the end of their days."
Mortality was originally called The Gift of Men, although after their revolt against the West, it came to be called The Doom of Men. When she renounced her own immortality, Arwen gained the The Gift of Men, but at the last moment, she lost all because of her abiding fear of death. This was the final triumph of The Shadow.
Maybe you have to have read The Silmarillion to gain a full appreciation for what happened.