"Unpredictable Family" is a family drama, with four characters as the main leads: Sun Woo, Eun Sung, Eun Hyuk and Ha Young.
Eun Sung and Eun Hyuk are half siblings. Sun Woo likes Eun Sung and Eun Hyuk likes Ha Young, but Ha Young likes Sun Woo and this mess is only the beginning. HAHAHA'
Sun Woo's mother is also Eun Hyuk's mother, she was married to Eun Hyuk's father but got divorced. Eun Sung is the daughter of Dong Goo and Choon Young, they were falsely accused of having an affair.
Eun Sung and Eun Hyuk have a sister named Eun Ah, she likes Min Guk, who's Ha Young's uncle... it's a crazy complicated family tree.

At some point, I really thought Sun Woo and Eun Sung were siblings, they should have cleared that way before, it started to get really weird. That was a more reasonable reason for the break up than the whole thing about the affair. To be honest, I couldn't take it anymore, Jung Ae was really being annoying, making herself look like a victim, even when everyone is telling her that the affair didn't happen, that it was a misunderstanding.

Besides everything else, the drama has 131 episodes, so it's not easy to watch, specially because the story is really confusing. Sun Woo and Eun Sung are cute together, but not enough to make the drama interesting. Eun Hyuk and Ha Young are a little better, but not much.
The best couple would be Eun Ah and Min Guk, but they are supporting characters and their romance is not really a priority, even at they only end up together literally at the end.