Love Scar

Both of these dramas are including the same male lead who is showing the same affection and performance.
It is based on the opposite concept for the male lead of being the younger in the old drama and the old in the newest one.
But though it is been 21 years difference between the both, where they embody the same characters of male lead in my opinion with same romantic genre story.
What is the common I think is that the relationship between the leads is not lasting for long time at the end of story and painstinkly resisting to not be separated.

When a man's ex suggests a three-person marriage with her boyfriend, the trio faces jealousy, social stigma and intimacy issues in their unique setup.

Manami is a female student who hates her wealthy family because they are fake. She meets Jun, a wealthy gay man, in Kabuki-cho, Shinjuku. They go to a male host club together and begin to share a host guy called Seiya.

In both, ex boyfriend returns in FL's life when she's in a relationship and they kind of end up cheating.

Ima is a single mother with a high school daughter. She has fallen in love again. The other person is Hisame, a graduate student about a decade younger than her. The two are attracted to each other, regardless of their age or circumstances. However, she already has a high school daughter and two other lovers. Ima, who does not feel jealous even if her partner has another lover, has taken the form of a "multiple love" with the consent and understanding of all involved, which is a free relationship but is definitely different from betrayal such as adultery Ima is a single mother with a high school daughter. She has fallen in love again. The other person is Hisame, a graduate student about a decade younger than her. The two are attracted to each other, regardless of their age or circumstances. However, she already has a high school daughter and two other lovers. Ima, who does not feel jealous even if her partner has another lover, has taken the form of a "multiple love" with the consent and understanding of all involved, which is a free relationship but is definitely different from betrayal such as adultery or cheating.

Asada Minami, a nurse, Hiruma Toko, and Nishino Yu, a bookstore employee, all fall in love with Kita-kun, also known as Manaka Kita, who has a mysterious charm that captivates everyone regardless of age or gender. In order to avoid increasing their love rivals, they form the "33% Club" to share Kita-kun's love in three equal parts. It is a love comedy about three people living together with Kita-kun.