korean drama about wife/girlfriend falling in love with another guy thanks

Valid Love - Main guy's wife starts cheating on him with this guy she meets. They start dating, but if I remember correctly they never go farther than kiss. Honestly can't remember even if they kiss. Also, in the end, her "love" for the other guy felt more like pity because he was a loner and she felt bad for him. She also used the other guy as an outlet because she married the main guy right out of highschool and never had an adult life outside of being married.

18 vs 29 (but it's played really light until it's not)

Discovery of Romance 

Jealousy Incarnate, kinda

Love in Sadness 

The good wife

I need romance 2

20 again

A Wife’s Credentials

One Spring Night

Films:

An Affair 1998

3-Iron

Before we get married

Secret love affair

My wife's having an affair this week

On the way to the airport

Love affairs in the afternoon