An article at legit.ng notes, unfortunately while seeming to use "polygamy" when it really means "polygyny," "5 places where women were allowed to have more than one husband"...
1. Nigeria The Irigwe people living on the western edge of Plateau, Jos are a unique people numbering around 17,000. This small group of people are known to be ardent subscribers of polyandry and it comes as no surprise as their distinctive language and social traditions sets them apart from neighbouring tribes. The Irigwe people of Nigeria practiced polyandry for many decades until it was voted to outlaw in 1968. Prior to that women were allowed to have 'co-husbands' and moved freely from one man's house to another, having multiple spouses, and their children’s paternity was assigned to the husband whose house the woman lived in at the time.
The article then goes on to name Kenya, India, China, and Brazil.
Traditional or not, an adult, regardless of gender, should be free to share love, sex, residence, and marriage (and any of those without the others) with any and all consenting adults. As such, anyone who wants to be married to multiple husbands should be truly free to be in such relationships. There is no good reason to deny such basic rights.

