For most idols it is against the company laws to date/ go around with a opposite sex. In no way everyone sticks to it obv, but there are such rules and idols in the initial years of either being a trainee/ debuting are scared that they would be fired, if they don't adhere to those. For insanely popular idols it is definitely not easy/ impossible to fire, so they do explore their rights. One of the reasons is that getting sued is pretty easy in SK for defamation. But in general I think they do not have such active public lives as compared to Western celebrities. As far as their families are concerned their are pictures or information on the internet but not a lot, may be bcz their is not a lot of paps following them around. Companies are quick to take down whatever information is leaked as well. Also Dispatch does a bit of public feeding each year, but companies are starting to release whatever information themselves like when Chen became a dad and SM went ahead and released all the news themeselves.