(no spoiler review) I watched this for Go Joon as I loved him in 'Misty' and 'Oh My Baby' (i really recommend both by the way). THEN i realised Young Dae was in it and I'm so glad he's getting the recognition he deserves! He played his character superbly. The acting was truly top class, shout out to Oh Min Suk who i thought stole the show, his character (Mr Ma) was very diverse and he showed a lot of skill with his acting. The cast truly made this show so good....but not so much the plot.
This is the reason why I left out the fifth star. Going into this i thought the plot would revolve around the main couple, and the husband's attempt to hide his affairs from his wife in fear of being killed by her. However by the 8/9th episode, the plot become almost confused and the rest of the show is all based on a murder case irrelevant to the main plot. The last episode was extremely rushed in my opinion and the very end was disappointing. The last three ish episodes have nothing to do with the husband and his wife but the murder case instead. I just thought it completely took away from the point of the drama. From the very start of the drama, viewers will be wondering (this isn't a spoiler dw) 'does WooSung (the husband) die? does his wife kill him?' which is a great opening but then the plot just weakens and weakens and is lazily put back together at the end.
However, the constant plot twists were very entertaining and each character was vital to the drama. A lot of kdramas that are focused on a lead couple often have unnecessary side characters but this drama definitely did not. From Mr Ma (Oh Min Suk) and Cha Soo Ho (Kim Young Dae), the two detectives and their odd chemistry, the ajumma, the paralegal and so many others. The script writer clearly valued each character which was great. The filmography is also pretty decent, there's some very satisfying transitions which is always a bonus!
Overall, I recommend that you do watch this kdrama, but don't feel like you necessarily have to rush to it :) This is coming from someone who has watched 50+ kdramas