It's the opposite lol black haired (Joohyun) is the uke and grey haired (Seojun) is the seme. Seojun used Joohyun for sex while Joohyun was inlove with Seojun at first but started to develop feelings for Joohyun and then fast forward Seojun got drunk and had sex with Joohyun with no protection so that's why now he's preggy and Joohyun isn't in the hospital for that reason (=・ω・=)

my memory is ass. Is this not the one where the gray haired guy used to mess w a guy black haired guy who looked insanely similar to the current pregnant character (bear w me w the names lol i forgot)