Why is it forbidden for a woman to have multiple husbands at one time?

Question

Praise be to Allah.

This
is connected primarily to faith in Allaah. All religions are agreed
that it is not permissible for a woman to have intercourse with anyone
except her husband. Among these religions are those which are undoubtedly
of heavenly origin, such as Islam and the original versions of Judaism
and Christianity. Belief in Allaah dictates submission to His rulings
and laws, for Allaah is All-Wise and All-Knowing, He knows what is in
the best interests of mankind. So we may understand the wisdom behind
the ruling of sharee’ah, or we may not be able to grasp it.

With
regard to the permissibility of multiple spouses for men and its prohibition
for women, there are several issues which are obvious to every intelligent
person. Allaah has made woman like a vessel, but man is not like that.
If a woman becomes pregnant (when she has had intercourse with a number
of men at one time), the father can never be known. People’s lines of
descent and lineage will be mixed up, families will be destroyed and
children will be lost. Women will be burdened with so many children
that they will be unable to bring them up and spend on their maintenance.
Maybe women would find themselves forced to sterilize themselves, which
would lead to the extinction of the human race. Moreover it is medically
proven now that one of the major causes of the serious diseases which
have become widespread, such as AIDS etc., is women having intercourse
with more than one man, and the mixing of seminal fluids in the woman’s
womb causes these lethal diseases. Hence Allaah has prescribed a waiting
period (‘iddah) for a woman who has been divorced or whose husband has
died, until enough time has passed for her womb and passages to be cleansed
of any traces of her former husband, and the monthly period also has
a role to play in this matter. Perhaps these brief pointers will dispense
with the need for a lengthy discussion. If the purpose of the question
is research for a university or other assignment, he may refer to the
books which have been written on the topic of plural marriage (polygyny)
and the wisdom behind it. And Allaah is the Source of strength.