I stumbled on an article about the Mosuo of China. They have a fascinating culture, and I realized that the Yhellani in my Sundered Tree novels strongly resemble them. It’s not a primary focus of my books, and I’ve added an option of marriage for people who have actually proven themselves fertile, but the elements are very similar.
Children join the mother’s family, and are raised by her relatives. Marriage to the father isn’t required, although it is an option, and multiple lovers are encouraged.
Nice to have confirmation that such a culture can succeed, and that I wasn’t so far-fetched in my imaginings.