Why does Mrs. Hale think that Ethan would have fared better if Mattie had died? Ethan Frome by Edith Wharton

At the end of Edith Wharton's gothic tale, there is a
Poe-like tone to the comment of Mrs. Hale. For, she implies that Ethan is trapped in a
living death.  The irony of his state is striking:  Instead of freeing himself from the
misery of cohabiting with a querulous and demanding woman he detests, he is now trapped
interminably with one who has become worse, the tragically injured Mattie, whom he
must be tortured by as a wreck of his love and hope.  Nor is there any respite from his
loneliness and anguish and guilt; his is now an irresolvable misery in which his love,
Mattie, has transformed into a mirror image of Zeena.