When Derek finally realizes that there’s nothing left for him in Beacon Hills, he goes back to New York, gets a life, falls in love and finds his home.
"Yeah, I just- I don’t know. I wanted to tell you." Stiles sounds confused by this. "I haven’t even told Scott yet. Isn’t that the weirdest fucking thing you ever heard? Like on a scale of one to were-lizard, this is like a unicorn."
"You’ve stopped making sense again."
"I know," Stiles sighs. "I do that. What happened tonight, it wasn’t real, is all, before I told you. Now it is. Jesus. I had sex. Why the hell am I telling you this? I should be telling Scott."
"So call him."
"I don’t want to. I want to talk to you. This big life thing happened and as soon as it was over, all I could think about was telling you."