Affair jdoramas are a dime a dozen. The ex flames who are now married is probably the second most used jdorama template besides boy meets girl.
Guilty is a Shinkawa Yua jdorama where she plays fashion magazine editor (what else is there) who's husband Koike Teppei is cheating on her and doesn't want to make babies with her. Shinkawa Yua runs into her old boyfriend who now runs an eatery. Unbeknown to Shinkawa Yua, her husband's mistress is actually her friend who she has been spilling her life story to.
On a side note, I am sick of fashion editor as a job in jdoramas. Its the easiest job to write about because they stand around and say this is good and this bad and when the story requires some danger, someone ordered the wrong dress or forgot the flowers. The shock and horror!
Anyway, Shinkawa Yua's mommy problems got her to break of her relationship in the first place and her mom is now in hospital. Things start to go wrong in her workplace and Koike Teppei's affair seems to be part of something bigger.
Guilty's worst sin is that it is boring. Absolutely no chemistry between Shinkawa Yua and old boyfriend. No sexual chemistry whatsoever. Guilty is an affair jdorama written for 14 year old girls. There's no fun and everything feels so bland. Avoid.