Hiroki, an average guy with no talent, is childhood friends with Kima, the ace of the swimming club. Despite feeling inferior to the honor student, the two enjoy a sweet romantic comedy relationship. However, the outgoing swimmer, Kosugi-senpai, suddenly interrupts their relationship, calling Kima by her first name. Suspicious, Hiroki becomes suspicious and suspects their relationship but Kima has been secretly dating Kosugi-senpai. Having assumed since childhood that he would naturally marry Kima, Hiroki is shocked but he takes her away from Kosugi and confesses his feelings. The two, who were in love with each other, confirmed their love but Kima's body was not a virgin and Hiroki was average... Faced with Hiroki's feeling of defeat, Kima seeks out Kosugi's huge cock and indulges in pleasure right in front of Hiroki's eyes. Later, after becoming a gravure idol in a lingerie outfit produced by Kosugi, Kima sends Hiroki her debut DVD... and Hiroki...
Thanks for the synopsis but man what a cookie-cutter plot lmao. I mean yeah there are only so many core ways you can tell a story like this, but these guys gotta start figuring out how to add some unique flairs and spice. Even if the story cores are the same, you can try to add unique elements to help keep them fresh.