Chronicle of a Blood Merchant (movie, 2015)

Set in a village right after the Korean War, poor but good-hearted Heo Sam-gwan sets out to win the most beautiful girl in the village, Heo Ok-ran, by selling his blood to earn money. Years later, the two are happily married with three children, but their family undergoes a crisis when Sam-gwan's eldest son doesn't resemble him and rumors spread about the boy's paternity.