Kyuuyuu to Furin shitemita

Ayuna Aki is an office worker who has been married for ten years, enjoying a quiet life with her loving husband... until she receives a postcard inviting her to a class reunion. That night, Ayuna dreams of her ex-boyfriend Tonoda and the intimate experiences they once shared. Whether asleep or awake, Ayuna broods on her encounter with Tonoda, aching with desire. As Ayuna wavers over whether to attend the reunion, she receives a message from Tomoka, an old school friend...

(Source: GOT, translated)