I had a very good relationship with a boy in my class when I was studying abroad. He even introduced me to his sister and her boyfriend. The boy's father and his sister's boyfriend's mother are college classmates and neighbors.
His sister and her boyfriend grew up together, and that childhood affection made them naturally lovers. It was time to talk about marriage. Tragically, the boy's father later objected. Later he learned that his sister's boyfriend was his father's own son.
His father and his sister's boyfriend's mother were lovers when they were in college. They always liked each other but didn't get married for family reasons, but they had a son between them. It may also be because of feelings that we have been neighbors for decades and helped each other no matter what.
Dog blood happened once around me, but at that time I was too young to understand things between adults. Now, I am particularly disgusted when I see this dog blood story. I hardly watch Korean dramas.