Hiroyuki tells us that he's already broken off his relationship with Kishida. He's sorry, but he doesn't want to invalidate what he feels. He knows that Kishida already knows that he loves Kishida, and he knows that it's not okay for Kishida to pursue him. He wishes he could have gotten to know Kishida better, but his feelings would get the better of him.
Hiroyuki tells us that he's already broken off his relationship with Kishida. He's sorry, but he doesn't want to invalidate what he feels. He knows that Kishida already knows that he loves Kishida, and he knows that it's not okay for Kishida to pursue him. He wishes he could have gotten to know Kishida better, but his feelings would get the better of him.