Second Love (2015)

Both have the same actress and emphasize the female lead feeling at loss because of their age. They both struggle to find what their own place in society as well as from misfortune in love.

A love story affair with a bit different storyline & plot with mature sexual content but both is worth watching drama. If you like mature love affairs story I definitely recommend this drama.

They are both about older women building up a relationship with younger guy. Both dramas gives out the same vibe.

A young ad executive's life has been turned upside down when a vicious client ruins his three billion yen project. Through his chance meeting with the disgruntled daughter of his enemy, he plans a vengeance scheme. The young woman agrees to play the victim of his bogus kidnapping.

Two persons who feel lost trying to comfort each other with skinship and learn because of each other how to go on with their life. In Kuzu no Honkai are just way more mentally damaged characters and it is more complex.

Both of these jdramas feature older woman/younger man romances, and both have male leads that are dancers. The progression of the romance is fairly similar, but Second Love is a lot faster with intimate scenes.

A love story affair with a bit different storyline & plot with mature sexual content but both is worth watching drama. If you like mature love affairs story I definitely recommend this drama.

Relationship between adults, male lead passionate about his artistic career, female lead changes her life due to her encounter with the male lead.

They're different (both the plots and the leads' relationship status) but, at the same time, I've found them similar (especially at SL's beginning; while watching I often thought about Hirugao).
Differences: the ending and the mood (they're both realistic but SL is lighter whereas Hirugao is more emotional, maybe because the latter is longer).

Two people are just drawn to each other despite social norms dictating that they should not be together. The notion of do you stay loyal to your family or follow your heart is displayed in both dramas.

They both have similar plot and themes such as the husband cheating and the wife having a younger man as a love interest.

A love story affair with a bit different storyline & plot with mature sexual content but both is worth watching drama. If you like mature love affairs story I definitely recommend this drama.

A man and a woman meet for the first time. The handsome stranger, asked her to spend one day with him. The woman has never taken a dangerous risk in her life. She has been with her lover for seven years and is going to get married next month. For the first time she will experience a level of excitement and intimacy, she has never experienced before with the man she met only today.

A younger guy falling for an older female teacher. However one is a student while the other is a professional dancer.

Both dramas are similar for their cheating aspect, both FL's are not satisfied with the relationship they have with their husband, thus, looking or accidentally looked at another man that appreciates their value more as a woman. They did not find the "other" man, they just happened to be in the right situation at the right time, and the "other" man caught their attention. The difference is that H has a sad ending, but OTWTTA has a happy ending, though not seen, just implied. And another thing, H is kinda steamy, but OTWTTA is more conservative, I don't know how they did it, but it came out nicely and sweet. H is also sweet and nice, but more sexy in my opinion.