That's... too much, Kai. Shinji was just getting comfortable with the idea that he can maybe look him in the eye, he drops that overwhelmingly warm sentiment down. He exhales slowly to stop himself from ducking back down in bashfulness.

He pulls away one of his hands, tightening his old with the other one to make up for it, as he reaches up to lightly pat Kai's cheek. "You're so important to me, too." He's too greedy to let go of him over something like this, as hazy as his feelings of it remain. "I love you, so... if this is just another part of you, I want... to be able to love it, too."

Surely, he can love the part of Kai that loves another person. He doesn't lose anything from it, and he's not going to reject that part of him on the slim chance that it will end up hurting him somewhere down the line.