Awaken as a Loser in a R18 Novel

An officeman woke up finding himself in somebodies room and different body, later on he found out he was born as James Kang. James Kang is a guy in an R18 novel he read that will get cuckolded by his girlfriend and the MC, Mario Jung who will fuck every female that get connected with him. "Pft...! Mario Jung! I was once jealous of you since you could get any woman you like. But since I got reborn in the same world as you are, I'll have to fuck the woman you're supposed to do with!" Let's join James Kang as he fuck every woman that has relationship with him and defeat the MC, Mario Jung. And will he be able to stand to the top in the highschool he's currently in?