You know why I love this drama so much? Because though it's an action, crime, thriller it's not westernized like other dramas are. Kdrama especially of listed genre tend to add the westernized touch of naked women, lots of cursing, high intense drug usage etc because they think these things make a series intense when all you need is good story writing and good story delivery.
ML nor his brother isn't acting like someone that has a child/niece and a girl at that. Watch a woman and tell me if she has a new man and you think it's, ok? Could be his daughter in the feature and he'd hope whoever doesn't go through with it.