This is a very sad story of a woman, who never get any attention or appreciation from her own family, even though she gave her whole life to them. She finds a way, quite unintentionally, to feel their love.
Even though her action are not fair, her family wont forgive her, wont understand her, and frankly, it seems they dont even love her. At all.
At the end she watches how her previously disfunctioning family became a better one - without her. Probably as the result of her actions, and it seems she became excluded forever.
It is her sacrifice for her happy family.
"What's a mother to do!"