What the Muslims don't tell you...

Female slaves were used for primarily for work. But they also provided
another service to their male masters ....

Relations with slaves is permissable.
23:05 YUSUFALI: Who abstain from sex,

23:06 YUSUFALI: Except with those joined to them in the marriage bond, or (the captives) whom their right hands possess,- for (in their case) they are free from blame

If a female slave is already married, relations are still permitted.

4:24 YUSUFALI: Also (prohibited are) women already married, except those whom your right hands possess: Thus hath Allah ordained (Prohibitions) against you: Except for these, all others are lawful, provided ye seek (them in marriage) with gifts from your property,- desiring chastity, not lust, seeing that ye derive benefit from them, give them their dowers (at least) as prescribed; but if, after a dower is prescribed, agree Mutually (to vary it), there is no blame on you, and Allah is All-knowing, All-wise.

33:50 O Prophet! surely We have made lawful to you your wives whom you have given their dowries, and those whom your right hand possesses out of those whom Allah has given to you as prisoners of war, and the daughters of your paternal uncles and the daughters of your paternal aunts, and the daughters of your maternal uncles and the daughters of your maternal aunts who fled with you; and a believing woman if she gave herself to the Prophet, if the Prophet desired to marry her-- specially for you, not for the (rest of) believers; We know what We have ordained for them concerning their wives and those whom their right hands possess in order that no blame may attach to you; and Allah is Forgiving,Merciful.


SAHIH BUKHARI - VOLUME 3, #432:
Narrated Abu Said Al-Khudri that while he was sitting with
Allah's messenger we said, "Oh Allah's messenger, we got female
captives as our booty, and we are interested in their prices, what is
your opinion about coitus interruptus?" The prophet said, "Do you
really do that? It is better for you not to do it. No soul that which
Allah has destined to exist, but will surely come into existence."

#9.093.506

#003.046.718

#009.093.506

#008.3371

#008.3432

All of these Hadith relate to Muslim soldiers having sexual relations
with newly captured female slaves. In some cases the women's husbands
were still alive. After a battle, the captured women and children were
divided between the Muslim soldiers as "booty", or spoils of war.
Marriage wasn't required to have sex with the females.

Listen to the
men's own words.... "we were interested in their prices", i.e., they
wanted to sell them. No Muslim man would marry a women intending to
sell her later. That is not what "nikah" - marriage was all about.
These men wanted to have sex with their slaves, enjoy them, and they
later sell them.

References :

answeringislam.org

Online Koran

Hadith search