My Aunt is raising her grandson as his mother left when he was a baby. She was married to my cousins but it didn't work out.
Polyandry is still practiced here. It's more common in societies with scarce environmental resources, as it is believed to limit human population growth and enhance child survival. Traditionally one brother would stay at home with the family while the other would go trading. I asked a family once if it caused jealousy, I was met with a blank look 'why would we be jealous?'