Responses
Basically, he thought he was cheated on by his over with his sister so he get his revenge by sleeping around to provoke his lover.
author didn't really specify if it, but i do lowkey think it might lean towards Kihun (blue-haired guy) since they did like each other but broke up because of a misunderstanding and Kihun still clearly loves him. they broke up bc silver guy thought he was cheated on by him with his sister (misunderstanding) so he kissed the military and had sex with other people after that (early chapters where Haekyong ran into them).
wtf, I'm so confused rn. Who's the real lover of the gray hair dude?! bcs he said he doesn't like cheating but he kissed the military guy while he's in a relationship with the blue guy ?!!! and he used to bring girls in their house