Is Monogamy Unrealistic?

Are men satisfied with only one women?  In some cultures  men are allowed to marry multiple women and have multiple mates. here in the US. we say thats a bad thing, But is it? Even the men that are in serious relationships and commitments find themselves being unfaithful at times. Is it because of greed or something else that is embedded deep down inside that says," I cannot  be put in a box by society and I'm a man and the women is my help mate, whats wrong with added more help to my circle? Im a KING and I have the right to have Culcha Bonds... Hmmmmm,