No, he can't. Kaiya isn't a "normal" guy and neither is Kou. Kaiya is a sadist and Kou is a masochist. In their relationship they both get off on things like neglect play and humiliation play. A normal person neglects a lover when they lose interest or become busy. In neglect play, the circumstances are just the opposite. The one neglecting their partner is paying strict attention to the response of their partner. It arouses them. The masochist understands and willingly accepts this from the sadist.
You can't grasp this kind of relationship because you are normal. There is nothing wrong with that. But more importantly, there is nothing wrong with the sadist and masochist either. A normal person might have a hard time dating a sadist or a masochist, but a sadist and a masochist are perfect for each other. This is why it is so great that there are so many different types of people in the world. Not everyone needs to be normal.
i dont think kou actually was a masochist though. he never shows any pleasure from pain and he can't even stand the sight of blood, so i dont think he really is one.
But Kou didn't know it was play - in an S&M relationship both participants are aware of what they're doing (at least they're supposed to be - not that I have ever been in a relationship like that but I have heard/seen responses from people in that circle saying that)... it's a relationship that deeply involves trust - Kou had no idea that he was involved in this kind of play. Kou might be an M, but he was being forced into things he wasn't comfortable with (he may have been ok with some of the play if he had been aware of the situation).
Please do not take this as an attack on SM couples, it's simply an observation on the characters in the story.
Umm.... couldn't Kaiya just ask Kou out normally, or just kiss someone else in front of him to make him jealous? But Kou is so freaking dumb to still like him