Derek stared at Stiles, stunned by the outburst and not sure how to handle it. He'd been okay with Stiles not being okay with being with himself and Isaac, but if the teenager liked it then he wasn't sure why he was upset.
He closed the distance between himself and Stiles, curled his hand around the boy's hip, over the brand that marked him as pack, as Derek's. "You fit here," he said, fervently. "I'm not ignoring everything you just said, because it's important, but this is more important. You fit here, Stiles. Everything else can be worked out, but no matter how it works out, you need to know that you belong here, just as much as Isaac does, and that everything that you think makes you less than Isaac just makes you different, and the only one judging you is you."