He's acting guilty and aware that what he did was wrong, maybe he really is? But saying he would just find other people is manipulative, in a way it is, because he's testing the uke when he obviously know that uke would be affected if he'll say that considering that they have a past. And idk how to explain it well, but yeah... It really is manipulative. Most of readers here can tell especially those who have read tons of toxic BL manhwas like this one. Lol.
Basically, Seo-in acknowledged that receiving consent for that one time doesn’t grant him permission to do whatever he pleases with MC. While this is an apology, it's merely the bare minimum, especially in that situation. Despite him stating, “actions speak louder than words,” MC clearly wants to avoid escalating the situation, saying, “Can we talk about this later?” Seo-in interjects by insisting, “But I want to do it right now,” which is manipulative as it puts pressure on MC, insisting on immediate action despite MC's prior discomfort (and discussion) with how the pacing of their intercourse being too fast. Hope that makes sense :)
thats so manipulative