10-nengo, Bed de Majiwaru Hatsukoi.

Minami is working toward her dream of becoming an actress in Tokyo when she is reunited with her childhood sweetheart, a man she hasn't seen in over a decade. Ten years earlier, when they were both in high school, Yamato suddenly abandoned Minami in their rural home town. Why did he leave without a word...? After being reunited, the two lovers ravage each other as though trying to fill every second that was stolen from their relationship. Minami slowly copes with her first physical passions and her rekindled feelings for her lost love, but Yamato has a secret that prevents him from being with her forever...
(Source: Renta!)