Koi to wa Baka de Aru Koto da
Finder
yaoi manga
There is a boy in love witb his friend but he feels that someone is stating a very strong or lusty gaze he thinks that that person is watching his friend so he goes to him and tells him to stay away from his friend the other guy refuses and threatens that he will make his friend his so all in all somehow the main person starts having a domewat physical relation with the other guy like kisses and all all the while main person thinks that he is a substitute but the other guy always loved the main person and just wanted to interact with him so he lied that he likes his friend also same as him
Hope this explains ifsomeone knows plz do tell i have a very weak memory and this story just keeps popping in my head
Sekaiichi Hatsukoi