Who is responsible for the maintenance of a woman pregnant from a void marriage (Nikah Fasid) or questionable cohabitation (Watu' Shubah)?
Chapter on the Condition in which Maintenance is Obligatory on the Husband
Al-Mughni
Book of Maintenance (Nafaqāt)
Primary text
If the maintenance is ruled to be for the fetus, both the husband and the cohabiting man are liable because the child is their offspring, thus making them responsible for its maintenance, just as they would be after birth.
Supporting text
If the maintenance is ruled to be for the pregnant woman, then the man is not obligated to provide it because she does not hold the status of a wife to whom maintenance is necessary.