Dakaretai Otoko Ichii Ni Odosarete Imasu.
2 rival actors are actually together. Lol I forgot the initial plot.
Abarenbo honey
Delinquent guy suddenly goes into heat in the middle of his fight with his rival who happened to be alpha.
Seifuku wo Matoeba, Umaku Uso ga Tsuketa no ni
One-sided rivalry with his childhood friend one day turns weird when he asks said childhood friend to pretend to be his boyfriend so this clingy chick could gtfo his life.
Miteranneeyo
Guy thinks this other guy keeps stealing his girlfriends so he tries to steal this girl he thinks the guy is macking on. Second story is between a senpai who suddenly kisses the kouhai while they were hiding from the rain. Last is a guy exchanging sexual favors for money from an older guy after his dad died and his sister is in the hospital.
Hide and Seek
Multiple Chapters but the first story is about a guy who finds his rival dating his sister and fights him in the street because of it. Other stories that I recall are about: 1. Wrestler and a pervy sponsor 2. Little brother obssessed with his older brother 3. Nerdy dude thats in love with a delinquent looking dude 4. Werewolf village 5. Guy in love with his senpai who's actually in a sexual relationship with the professor I forget the others but yeah.
All About Lust
Guy fell in love with his seunbae, confessed, and the sunbae said he likes him too but in a more sexually aggressive way lol. Second couple is two guys who are rivals and have opposite views about graphic design and art but for some reason are really sexually into each other all of a sudden. Jungmin is MVP. Best friend anyone could have. Real curious about JJ and Hyunho, though.
Shitsuji Kanzaki No Yuuutsu
Butler has had a thing for his slutty master for a while now and gets an opportunity to act on it. Rival tennis (?) players. Some story about them too.
Hanakoi Tsurane
2 high school kabuki actors, one has a one-sided rivalry with the other. The other one is obssessed with becoming kabuki partners with the other and the other misinterprets it as the guy being in love with him.
Ameiro Paradox