They weren't in love, it was convenient for them to sleep together. Except there might be feelings at least for the (now) omega. The alpha is possessive since high school.
The blond guy said "even if none of it was real" so it looks like he made the black haired guy an omega on purpose. We don't know if he planned it from the start but since we see him poking holes into the condoms he definitely wants him to completely transform into an omega.
Well, Yoshiki (blonde guy) did plan on making Tsukasa (black haired guy) his from the beginning but he didn't know that Tsukasa would turn into an omega.. Just lucky for him.. And he intends to use this to fully make Tsukasa his..
Thx that helps a lot ,
Can someone explain to me , what happened . Like I read the hold thing but I don’t get it... like I thought they were in love . But I don’t get the twisted part