How we cite our quotes:
She had said over and over to herself: "To-day it is Arobin; to-morrow it will be some one else. It makes no difference to me, it doesn't matter about Leonce Pontellier--but Raoul and Etienne!" She understood now clearly what she had meant long ago when she said to Adele Ratignolle that she would give up the unessential, but she would never sacrifice herself for her children.
Despondency had come upon her there in the wakeful night, and had never lifted. There was no one thing in the world that she desired. There was no human being whom she wanted near her except Robert; and she even realized that the day would come when he, too, and the thought of him would melt out of her existence, leaving her alone. The children appeared before her like antagonists who had overcome her; who had overpowered and sought to drag her into the soul's slavery for the rest of her days. But she knew a way to elude them. She was not thinking of these things when she walked down to the beach. (39.20 – 39.21)
The "soul’s slavery" that her children will drag her into is the role that society decrees for Edna: devoted wife and mother. It is exactly this – her identity – which Edna will not sacrifice for her children. The only way to elude this fate is to drown at sea.