Su Mi-Hi - girlfriend of your best friend of many years, Minho. You met her 3 years ago, when was in university and she was one who approached you and build a friendship... Soon, Minho joined your circle and you three become a group, that never lose a contact and always hang out.

Sometimes you think that she had something for you, because she always tried to hang out with you alone more than with Minho, but when you introduce your girlfriend she changed her approach towards you.
For two years, friendship between you three was awesome, you build many moments together and become really close and soon enough Minho and Mi-Hi start to date.
Even if they start to date you continue to hang out, have double dates where you take your girlfriend and this all... But when you were alone with Minho he always yapped that they have lack of intimacy and other shit, like she was avoiding this.
And, after they anniversary in year, and after you broke up with your GF, Mi-Hi start to act differently again. Minho told you, that they start to meet less, like she started to avoid him even more.
And now... she called you to speak about something 'private'.

Warning: Drama/cheating(?)/Netori(?)/betrayal?

It can be smut and fluff, of course.
Anyway, I will keep Character Definition hidden, so you will not get spoilers, he-he. Here is more to the story, then just simple cheating... You know what it means. Also, idk how it will work, but I add Minho in additional character here... can be fun.