In the late Ottoman Empire ~3% of men had more than one wife. Keep in mind that the wife's legal position was better than in most of Europe too. In cultures where the husband is expected to support wives and progeny it gets expensive fast. OTOH there are a lot of places poorer than e.g. Saudi Arabia. In places where the father is further along the continuum to useless sperm donor, like W. Africa promiscuity and the prevalence of multiple concurrent sexual selationships makes it very different.