Despite the other Guardians' doubts, North found out for you and Jack, that it indeed is okay for a Guardian to have a romantic relationship. Not with a human, though. Fortunately for you - in some ways, anyway - a tiny seed of Pitch's dark magic was left in you, and for reasons unknown to you, Jamie, and the Guardians, it has altered you just enough. The Man on the Moon informed you of this. That's the only thing that he's ever said to you. That tiny bit of magic is just enough so that you can stay with Jack forever, if you both desire. You know that you do, but you're a bit worried that Jack won't want to. You're worried that he's going to leave you. And all of this has happened within hours of returning from your little "stay" with Pitch. After the Guardians made sure that you were alright, Jack brought Jamie home.
Now, you walk through the cold, dark streets with him, pressed into his side, although it offers no warmth. You don't say anything, because there's nothing that needs to be said right now. You're both just content watching the snow fall all around you. When you get to your house, Jack convinces you to let him fly you up to your room, as it'll minimize the amount of sound you make, and melted snow you leave on the floors. You wrap your arms tight around him, and once your feet are planted firmly on the ground, you whisper, "Jack, thank you for everything…"
He chuckles, "[y/n], you're making this sound like a goodbye! I'll see you again!"
"Y-yeah… I just wanted to tell you, though…"
"Well, uh, I'll be going now, I guess…" Jack says, almost sounding nervous. The next thing you know, he already has one leg out your window.
Without thinking, you whisper frantically, "No! Please, please stay with me! I don't… I don't want you to be gone…" A look of pleased shock comes onto his face.
"Should I go stay on the couch then?" He asks. You shake your head.
"No… please… stay with me…" He walks closer to you, and you look up at him, pleading with your eyes, hoping that he'll understand how much this will mean to you. You're terrified that when you wake up, he'll be gone… and how much easier would it make that if he wasn't even in the same room as you?
"You're getting quite bold, aren't you? I think it's cute," he says as he rests his hand on your arm. "Now, go put on your pajamas, okay? I promise, I'll be waiting right here when you get back." You nod and grab a pair of sweatpants and a hoody, and look at him one last time before going to get changed.
As promised, when you walk back in a few minutes later, he's simply flipping through an old photo album of you and your parents together, and some old friends, but mostly of you and Jamie doing various things; having a hotdog eating contest, ice skating, giving each other piggy-back rides, playing an intense game of chess that involves throwing the pieces at each other - not hard, of course - and so many more random activities that gave your friendship spark. You're so happy you have him back safe and sound. Then, when Jack notices that you've returned, he sets down the thick album, lifts you up, and then settles you into your bed. As he lays down next to you, with an innocent space between you, he says with a slight smirk, "Just warning you, you're probably going to be quite cold tonight."
"I sort of figured as much," you say, chuckling. Another comfortable silence settles over the two of you, as you look up at the dark ceiling, thinking, and he gazes at you.
"You know, [y/n], I think that I really, really love you…" You can hear the seriousness in his voice, and you look over at the winter spirit. His icy eyes match his tone, but hold a sweet warmth in them. You close the space between you, resting your head on his shoulder.
"Jack, I love you too," you murmur before he places a gentle peppermint kiss on your lips, as he laces your fingers together, frost covering your skin. You fall asleep with Jack Frost nipping at your nose, from that night on, to the end of time.