A/N: Sort of a follow-up to The Devil Plays all the Best Tunes, though you don't have to read that one to get this one.
It's been seven months, three weeks, and four days—not that Tony's been counting or anything—since he first slept with Loki, and he's starting to think it might be more than just sex.
In the beginning, that's pretty much all it was: three or four times a week, Loki would show up in Tony's room and they'd fuck like rabbits, all long limbs and tangled sheets; depending on how late it was when they stopped—and usually it was four in the morning—Loki would stay the night, and sometimes he'd stay for breakfast, eating quickly and silently, casting occasionally glances at Tony over his plate which the engineer could never decipher, no matter how hard he tried.
And then he started talking to Tony, after the sex, leaned against the headboard with one arm draped casually behind his head and the other hand splayed out across Tony's chest, or threading gently through his messy brown hair, just talking about stuff. Sometimes it was personal—they talked about relationships and their families and Loki always clammed up when pressed to mention Laufey or any of the other Frost Giants—and sometimes it was about their work, and sometimes they just joked around, until one day Tony realized they'd moved past the snarky, snide comments and were in the quick witty flirting zone, and it wasn't all entirely innocent.
And then Loki started staying past breakfast, and there were times when he'd actually stay with Tony for an entire three days straight, and actually he wasn't unpleasant company outside of the bedroom. They challenged each other intellectually, and it was actually fun, having someone around who wouldn't ask fucking stupid questions, like 'what the hell is quantum theory?' or 'isn't that the part of the car that goes in the back, Tony?' because Tony actually doesn't need to hear that kind of shit when he's trying to focus on a physics equation. They flirted psychologically, they had intelligent arguments which left Tony's head reeling, they discussed the properties of magic and science and how they tie in with each other so closely. They even had sex in the lab once, with the edge of the marble-top table digging into Tony's back, but decided it probably wouldn't be worth repeating when they discovered in the morning that half of the engineer's tools had been destroyed due to the power of Loki's magic.
It's been seven months, three weeks, and four days of this—sex, banter, laugh, stare into his eyes and pretend you don't see how they're softening at the edges, trace the sharp outlines of his cheekbones with your thumb because he's allowing you to, eat breakfast and notice he's wearing your shorts, read The Great Gatsby with him and laugh when he asks why the hell Tom was such an asshole, fall asleep on the couch with him because the movie stayed on too late and the sex wears you out, repeat—but Tony's only just starting to clue into the fact that it's branched out way beyond the bedroom at this point.
Okay, so maybe he's sort of noticed it before now, but he wasn't going to admit it to himself, that he loves seeing Loki sitting at the island in the morning, drinking coffee and reading the newspaper and not even bothering to hide his fascination at Midgardian entertainment. He wasn't going to admit it, but then he and Loki fight, and Loki goes off and blows up half of Soho, and he starts to wonder if it's the mental instability or something else.
It's a stupid reason to fight, in Tony's opinion: Loki sees him at their favorite hangout—the library, not that Tony will ever admit to it—talking to a girl he used to date back in the day, and the god gets jealous, and the next thing Tony knows he's in their bedroom, and he's getting read the riot act. At first, he tries to reason with Loki—I wasn't flirting with her, Jesus fucking Christ; you know I have been monogamous to you since… this started, and that's saying something, Loki—but the Jotun-born Aesir isn't listening and Tony's getting sick of hearing an echo of his dad yelling at him for 'sleeping around when he should have been studying', so without thinking he snaps:
"Jesus, Loki, get a grip; you're sounding way too fucking much like Odin," and the next thing he knows he's alone in the room, and then a few minutes later JARVIS tells him Loki's blowing up Soho, and Nick Fury's calling him and wanting to know why the hell his boyfriend's gone bat-shit crazy again, and now Tony's seeing that yeah, it's definitely more than just sex, and he should've commented on that little fact back when he first looked over at Loki and saw a flicker of amused affection in his eyes.
Instead, he has to suit up and fly out to Soho—and it's not a far flight, but to Tony it takes hours—and when he gets there Loki's sitting on the roof of a building, blasting in the windows of a car across the street, his face expressionless. Tony lands next to him and flips up his visor so he can see Loki properly, and… oh god, is he crying?
"Fuck off, Stark," says the god without turning. His jaw is set. Tony glances down at the street, where the other Avengers have started to assemble, and shakes his head briefly, letting them know he can handle it up here for the time being.
"Loki," he says. "Come on. Why—"
"You know damn well why," Loki snaps, and another window shatters, fire leaping out and sparks flying.
Tony is smart enough to realize that this isn't about Loki being compared to Odin, not really. "I hadn't seen her since high school."
"So that justifies you flirting with her?" The god is standing and walking towards Tony, and his heart starts racing behind the arc reactor, because there is nothing pleasant at all about the expression on his face right now; actually it's sort of demonic, and he's considering flipping his visor on again and calling for Steve or Thor to come up and handle this, because he knows Loki will kill him.
"I wasn't," Tony repeats, backing up half a step. A brief picture flashes through his mind, of Loki draped over the couch in nothing but one of Tony's nightshirts, and he shuts his eyes, swallowing. He is going to lose that if he's not careful. He is going to lose it all, and it's been seven months, three weeks, and four days, and it's not all about the sex anymore, and he's just starting to realize that now, and it sucks, because his chest hasn't been in this much emotional pain since he and Pepper split up. "I swear to you, Loki."
A brief, pained look crosses Loki's face, and then it's gone, and his arms are folded and he's frowning. He opens his mouth to speak and fear thuds in Tony's chest and he blurts:
"Honestly, why would I be flirting with anyone else, Reindeer Games? I got you." It's probably the stupidest thing he's ever said to anyone in his whole life, and he makes up for it by adding, "I wouldn't just throw away seven months of the best sex of my life for a chick who I boned when I was seventeen."
Loki rolls his eyes and mumbles something, too low for Tony to hear, but his cheeks are slightly flushed, and after a few seconds he asks:
"The best sex of your life?"
Tony grins. "Yeah," he says, because it's the truth, and it's also easier to admit than having to say 'I've been happier with you than I've ever been with anyone else, so why the fuck would I cheat?'
But he suspects Loki can tell that's what he's thinking, because his emerald eyes are softening, and he closes the space between them and their lips meet, and Loki's arms go around Tony's waist, pulling him closer. There are whistles from the Avengers who are still down on the street, but both the mortal and the god ignore them. Tony's lips curve into a smile and he twines his fingers in Loki's hair.
"Shall we go?" Loki breathes after a few minutes, barely stepping away from Tony, his lips still brushing the engineer's as he speaks and stares into his eyes.
"After you," Tony murmurs, sliding his visor back on and informing JARVIS to call for pizza in five hours, before Loki grabs him tighter and teleports them both back to the tower. They land in their bedroom, and JARVIS removes Tony's suit with remarkable speed, and then they're in a heap on the bed, and Loki's grinning devilishly up at his lover, and Tony's capturing his lips again, claiming him.
It's been seven months, three weeks, and four days since Tony started his dysfunctional, strange, emotional relationship with Loki, but today is the first day that he can really admit to himself that he's fallen in love with the Asgardian god.