"Indeed, from a logical standpoint, the illegality of polygamy seems grossly unfair. If a man has a wife, and then takes a mistress, it is perfectly legal. He can have sex with her and use her for her body without any legal repercussions. But the moment he takes responsibility for her, contractualizes the relationship, and makes an honest woman out of her by marrying her, they throw him in prison." -- Rabbi Shmuley Boteach, "Homosexuality Is A Religious Sin, Not An Ethical One"
( The author is not actually pro-polygamy... )