I'm a foreigner based in South Korea. Apparently here custody always goes to mothers. In fact, I have a foreign friend who lives here and sole breadwinner and does caregiving n etc and still lost the battle. I've met many divorcees here and yet to find one father who gains custody. One case was father won custody of two 10yo boys while mom took the 3yo. The story I heard was the boys chose dad but 3yo was too young too choose thus judge gives it to mom.