Sasano Kaori and her husband are very close, but Kaori starts to notice that her husband has "changed." One day, while talking to her best friend Yuki, Kaori learns that Takuya has a secret account with many posts hinting at an affair. Kaori later discovers that the partner is Mishima Mutsumi and visits Mutsumi's husband, Kyosuke, to ask for his cooperation in separating Takuya and Mutsumi. Kyosuke agrees on the condition that Kaori sleeps with him. While following and monitoring Takuya and Mutsumi, Kaori begins an affair with Kyosuke and eventually falls in love with him.
(Source: DramaWiki; edited by MyDramaList)
~~ Adapted from the manga series "Watashi no Otto wa: Ano Ko no Koibito" (わたしの夫は―あの娘の恋人―) written by Aizawa Atsuko (あいざわあつこ) and illustrated by Gin Tsukishiro (ツキシロギン).
