[Goldmine]

Mistress is haram, period. Zeena (sex outside of marriage) is a very shameful act in any Muslim society, even today. 

As I've said in another post, Islam offers a solution to men's appetite for sex. And the women are protected.

So the solution is allowing men to have sex with  many partners as many as four but got to legalised it first thru marriage. That is a genius way to get round the problem of committing adultery. An added bonus being a Muslim.

 Whose idea was it for setting the limi? Was it by one of the prophet. The others agreed?

My apologies again if I unwittingly offended Islam/Muslim.