Nafaqah as the wife's right unless she gives it up
Q 4: What is the ruling on a man
married to two women but providing for only one of them?
Nafaqah (obligatory financial support) is the wife's right and it is permissible for her to waive it, if she so wishes. Yet, if she does not waive it, the husband is obligated to financially support and treat his wives on an equal basis, according to his capacity. Otherwise, he will be committing a sin and will come on the Day of Resurrection with one of his sides split. Allah will expose him before all the people as reported in a Sahih (authentic) Hadith from the Prophet (peace be upon him). Moreover, the wife is entitled to claim her rights defined by the Shari`ah (Islamic law), and the husband is obligated to fulfill. Allah (Exalted be He) says:
Let the rich man spend according to his means; and the man whose resources are restricted, let him spend according to what Allâh has given him.
Also, Allah (Exalted be He) says:
...but the father of the child shall bear the cost of the mother’s food and clothing on a reasonable basis.
The Prophet (peace be upon him) said,
"It is enough sin for a person to withhold sustenance from those they are responsible for."
The Prophet (peace be upon him) also said,
"Anyone who (Part No. 19; Page No. 204) is married to two wives and inclines to one of them will come on the Day of Resurrection with one of his sides hanging down."
(Related by Imam
Ahmad and the Four Compilers of Sunan; Hadith compilations classified by jurisprudential themes)
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.