What The Friend?!

Kang Jae-Yun, my mom's friend's son and my ex-boyfriend's buddy. Of all people, I end up witnessing my boyfriend cheating right alongside Jae-Yun...?! Jae-Yun comforts a drunk Sung-Ah, but there's something strangely off about his vibe?! Having a guy friend is one thing. But Kang Jae-Yun... “Jae-Yun, could we stop being friends?”(Source: Bomtoon, translated)