Would Islamic law condone this injustice inflicted upon a wife who returned to her husband on the condition of remarrying for the sake of her children, only for him to abandon her a week later to marry another woman without consummating the marriage, under the pretext of illness? And how should she act in this situation?

A husband must treat his wife with kindness and fulfill her rights, including sexual intercourse according to her needs and his ability. A wife is justified in seeking a divorce if she is harmed by her husband's failure to engage in sexual intercourse with her. If he marries another woman, he must be just between them in terms of lodging and expenses, as Allah Almighty says: "Then marry such women as seem good to you, two, three, or four; but if you fear that you will not be able to deal justly [with them], then only one." If the husband is ill, it is advisable to be patient with him, help him with his treatment, and not rush to seek a divorce, especially if there are children. If a divorce is unavoidable, Allah Almighty says: "But if they separate [by divorce], Allah will enrich each of them from His abundance. And Allah is ever-Encompassing and Wise."