Tragic ending makes me hate the movie.
After returning from his time jump. His wife is no longer dead and they live happily ever after.
But. . .
We know that he remembers what has happened while he is travelling through time. He is not affected by the changes in the time stream.
So she has lived the past however many years with him that he will never remember. Years he spent missing the love of his life, who has now grown and changed.
He doesn't remember the years that have passed now, and she does not know him at all. He is a different man.