a marital system that consists of having more that one husband, called polyandry 1人の妻に2人以上の夫をもつ,一妻多夫制という婚姻制度 - EDR日英対訳辞書
unfortunately, since polyandry was not permitted in the United States she would be compelled to forego the honor and happiness of marrying either of them.
あいにく、アメリカでは一妻多夫制が認められていないから、どちらとも結婚するという喜びと幸せは諦めないとだめだって。 - JACK LONDON『影と光』