it wasn't shown in detail but yeah his first love "betrayed" him back in highschool ig...so he became a player who's into fucked up plays during seggs and doesn't wanna have deep feelings for anyone ever again.
also completely unrelated but the MC looks like plave's yejun and his childhood bestie looks like hamin. I can't unsee it anymore
on this korean site called newtokki
here's the link you can copy paste the korean name from here onto the search bar -
https://newtoki467.com/webtoon?toon=BL%2FGL
damn like if y'all don't want us rooting for the 2nd ML, don't make him the better choice??? don't make the ML be some asshole who's taking out his frustrations of his failed first love on others while making the 2nd ML be a wholesome childhood friend whos loved the MC since childhood!! I CAN'T!! ༼;´༎ ༎༽