Saving the world takes its toll.
Saving the world has a high body count.
Saving the world shortens lifespans, even when it creates so much more to live for.
They fall together the way they always should have. Some near-death experience gets Tony's head out of his ass, gets Steve's priorities in order, and they find themselves in a room together, broken and battered and bleeding, mouths sewn shut with effort to prevent years of words bursting forth, breaking the dams.
Yet despite everything, despite the rift they'd dug together and torn apart even further, it's exactly as it should be. He's not Tony's first love, and Tony's not his, but they are each others' last loves, and that's the important thing.
They retire.
(There is no parade in their honor.)
They get married on a beautiful afternoon in October 2020, fifty-year old Tony Stark and one hundred-something Steve Rogers, and it's all eye-watering golden sunlight and nothing but warm and home and everything when Clint, of all people, pronounces them married in a small ceremony in Malibu, and when they kiss for the first time as husbands Tony's perfectly trimmed goatee gently scrapes against Steve's skin, and it keeps Steve from believing it's all been a dream, that he'll wake up in 1942 or half-frozen in 2011.
(Tony, strangely enough, hadn't pestered Steve for a big wedding—something televised and gaudy, with hundreds of the rich and famous in attendance, but Steve knows that Tony is relieved at how intimate the ceremony is—just the team—even Bruce, dug up from some tiny island somewhere—and friends on a cliff somewhere in Southern California during a sunset so beautiful and startling as to be utterly cliched.
If Tony had ever somehow gotten himself hitched before Afghanistan, Tony tells Steve with a devious smile, it would have been a total Kardashian wedding. Steve replies drily that Pepper would never have let that happen, and he's right.
Clint manages to become certified to perform weddings on the internet about ten minutes after he hears the news of their engagement—which, despite Steve's now-secure acclimatization to the twenty-first century, still seems a bit much.)
The ceremony had been the fun part. The less fun part had been the paperwork. Apparently marrying someone worth a medium-sized country's GDP means lots and lots of paperwork, and wills with clauses the length of several novellas, because everyone has always wanted a piece of Tony Stark, and after he dies they will cut him up and descend like vultures, enjoying him dead more than they ever did alive.
Steve knows it's for the best, of course, but he really doesn't like thinking about the circumstances in which Tony's last will and testament is even necessary.
Tony sees Steve fiddling with the pen, unable to bring himself to look at the document on the attorney's desk requiring his signature. His agreement for a cut of Tony Stark's body, as if any amount of money would matter when there is no longer a Tony.
Tony smiles broadly to mitigate Steve's concern, but it doesn't reach his eyes.
"Don't worry about me, Cap," he says, voice bright with false cheer, clapping Steve heartily on the shoulder. "I'm gonna live forever. Even if I have to transplant my brain into a robot—I'll figure something out, you'll see."
He doesn't.
Anthony Edward Stark dies on April 26th, 2040, at precisely 2:13pm, eastern time.
Steve is holding his hand when the deeply-etched lines on his forehead smooth out for the last time.
It's frankly a miracle he has made it this long, the doctors mutter amongst themselves, and he is lucid until the last—well, as lucid as Tony's particular brand of playful flirting and complicated technobabble really can be, wonderfully agile of mind and quick-witted even if he couldn't get out of bed anymore, which he hadn't been able to for months.
His liver hadn't really been doing what it was supposed to for around a year, having spent much of Tony's life marinating in hard liquor, and even swearing off the stuff after Afghanistan hadn't been enough to bring it back up to fully working order.
His heart: weak even after the surgeries to remove the arc reactor and reconstruct his rib cage and sternum way back in the day. The palladium problem had been remedied, true, but the amount of stress his body had been under that whole time took its toll. And the years after, and the years after, and after, and after and after.
Lungs: also not totally great, thanks to the arc reactor, though also not painful enough, apparently, to stop Tony from taking a few bong hits every now and then to relax. Or maybe not—Tony had never been good at knowing when his pain threshold had been crossed, or at listening to his body even when he knew he'd gone too far. His eyes had gotten so nearsighted due to all the tiny, detail-oriented work in the lab that he would be swept up by for days at a time that he'd had to wear glasses starting around his fifty-fifth birthday, much to his chagrin.
(Steve hadn't minded them all that much—he'd even thought they were cute—even though they made spontaneous surprise kisses a little harder to pull off).
His hair is entirely gray, without a trace of that rich dark brown left, but that had happened around seven years prior, and Steve had consoled Tony by reminding him that it could have been worse—his hair, steely as it is, is still luxuriant and thick and excellent for grabbing onto when necessary.
(His goatee fares better; it's several shades darker than the rest, and isn't that a relief, because if it had gone any paler Tony'd have to have slapped on a red cap and called himself Chris Kringle.)
Steve makes himself watch as the nurse presses Tony's eyelids closed, and feels like he's been frozen alive again.
Anthony Edward Stark dies at age sixty-nine (a number which he had enjoyed to no end, despite the whole dying thing), and Steven Grant Rogers looks not a day older than thirty when he stands in front of the steadily dwindling number of people who had loved Tony Stark in a black suit, watching the finely crafted mahogany casket being lowered into the ground and not caring who sees him cry.
"Please tell me nobody kissed me."
He half-expects Tony to sit up in his coffin, lively and irritating as ever.
It's not many people who are even around anymore to mourn. Pepper is there, of course, elegant and fine-boned behind the fine lines covering her face, accompanied by her and Happy's daughter Maria, named, of course, for Tony's mother. Rhodey is there as well, naturally, accompanied by a tall grandson in military dress pushing him in his wheelchair, cropped hair gone white with the stress that came along with being Tony Stark's friend, but Rhodey doesn't seem to mind. Happy had died years ago—some kind of organ failure, perhaps—Steve can't really bring himself to try and remember. Coulson and Fury had also passed, though they'd been the oldest in their little club, their "Super Secret Boy Band," as Tony had put it so long ago, and being old is apparently a sickness and a death sentence all by itself.
(Steve wouldn't know. Bruce had told him years ago that because of the serum and the stasis his body had been forced into for seventy years, Steve would age at about half the rate of an ordinary human. Tony had cackled at that, declaring that all was right with the world because Steve's perfect twenty-something year old's ass would continue to remain positively edible, that he would continue to be Tony's young, fresh arm candy forever, making Steve blush and Bruce turn white as a sheet.)
(Of course, Fury had been officially dead for decades at that point, so they couldn't have really done much by way of a real funeral when he'd passed, but they'd poured champagne into crystal flutes and taken a few moments to remember the crotchety old bastard, who, despite his faults, had managed to bring them all together, and wasn't that something.
Yes. Yes, it was.)
He'd been too old when he'd woken up in the ice, and now he's too young. Too young to go jogging with Sam, whose knees keep giving him trouble, and Steve can see that it takes him too much effort to pretend to try to keep apace. He's too young to really spar with Natasha like they used to, because although she won't admit it, she's got the beginnings of back problems. And don't get Clint started on his shoulder strain, because that just depresses the hell out of both of them.
Watches Clint and Rhodey and Sam become grandparents. Watches the gray in Natasha's hair overtake the red, sees her smile as she tries to shrug off the vestiges of her vanity.
Sees Bruce Banner's obituary tucked quietly into a corner the next-to-last page of the front section of the New York Times , just as he would have wanted-nothing elaborate, no photos, and only a glancing mention of the Other Guy.
He is there when Wanda, strong and graceful but brittle with age, sits on a couch with Nathaniel Pietro Barton and tells his newborn daughter Philippa about her papa's namesake.
(Nathaniel had asked Steve if he would be okay with giving his daughter the name Antonia, but it's still too much. It will always be too much.)
Even if Steve had wanted to forget Tony Stark, it's not possible. Both in the tangibles and the intangibles. During his life, Tony had been a media fixture from the tawdry spreads of Page Six to the cover of Scientific American. He'd been on television more times than Steve can count—ever since he'd proven his genius at age four by building that circuit board, anyone with a television—and later, an internet connection—had been able to watch him grow up, watching the sad, lonely, alienated boy become a sad, lonely, alienated man with a better public face, watching him drown himself with the twin vices of too much work and too much pleasure until Afghanistan, watching him—all of them—back when they were the Avengers, back when they fought Loki and Ultron and Doom and Stryker and one another. Back when.
—Tony at press conferences, Tony at the Stark Expo, Tony presenting and receiving various awards, Tony being interviewed on programs as different in tone and audience as 60 Minutes and The Soup and being as charming as ever, Tony running (and driving) in loopy drunken circles away from paparazzi—even the several sex tapes still out there, as grainy and crass as they are, because a horny twenty-something Tony Stark plus a video camera could only have been a recipe for trouble—
There's enough footage of Tony Stark out there to occupy Steve for several lifetimes.
And all he has is time.
Their graves are scattered now, but Steve has all the time in the world to lay wreaths.
He can't help but smile when his hips, finally, finally, finally begin to ache as he kneels to press a kiss to Tony's tombstone.
(It's only a matter of time now, and Steve knows about waiting.)