When he answers the call, it’s to Steve’s panicked voice on the other end. “Tony? Tony, I don’t know what to do. I’ve been thinking about this for so long only now we’ve actually found him and I can’t—I don’t—”
“Okay, whoa, calm down Cap, what’s going on? Do I need to get the suit and fly over there?”
Steve takes a few shuddering breaths. “No, no it’s…we’ve found him, Tony.”
“Barnes? Isn’t that a good thing?”
“Yes! I think. I mean, it is…”
Tony puts down his screwdriver and plonks himself into his office chair, heaving out a sigh. “I am really glad I skipped that board meeting today because this sounds like it’s going to be a Serious Conversation.” He shoves himself away from the workbench and into a resigned spin. “Okay, shoot.”
“Bucky and I, during the war…we were together. But then he fell and I woke up here, and I thought I’d never see him again. I tried to move on, and I thought I had, but now that he’s back…” Steve takes a breath, and his next words fall out of his mouth and into the pit of Tony’s stomach. “I still love him.”
Tony has to wrench his mind back into focus because Steve is continuing on in a rush.
“I think I never stopped, even when I started this thing with you, but Tony, I love you too.” There’s a pause, and Steve sounds miserable when he repeats, “I love you Tony, and I don’t know what to do.”
He takes a deep breath, trying to quiet the churning in his gut, and lets it out slowly. “I believe you—”
“Tony—” There’s a note of warning in Steve’s voice because he’s Tony fucking Stark and even his insecurities have insecurities, and he’s damned if Steve can’t see through all of them.
“Okay, okay, I’m trying really hard to believe you because you’re Captain America and you’re a terrible liar and if my years of scandalous escapades have taught me anything, it’s the million variations of human sexuality. It sounds like you’re polyamorous, which—” he cuts off whatever Steve was about to say, “—is totally fine because why do you think Pepper broke up with me?”
“I thought it was because you wouldn’t give up being Iron Man.” Steve sounds confused, like he can’t quite process all the words that have just come out Tony’s mouth.
“Well, there was that, but there was also the fact that I was (and still am) head over heels for you and Pepper couldn’t accept that I could love her just as much while still having feelings for you.”
Steve lets out a small “Oh.”
“I am probably going to regret this because I’m terrible at sharing, but I also never expected to have any of you, so…I’m not going to get in the way of you having Barnes too.”
“Tony…” Steve sounds pained, but Tony doesn’t want to hear it.
“Just…bring him home, okay?”
When Steve does show up with Barnes several weeks later, the former assassin is tense and withdrawn. He doesn’t speak, and follows Steve around like a second shadow. They can get him to nod or shake his head, and if they’re lucky they’ll get a word or two. Sometimes Natasha can get short sentences out of him in Russian. He’s more forlorn than aggressive, though, and if he’s given a direct order he’ll usually just ignore it, so they’re pretty sure HYDRA’s brainwashing is mostly gone.
Steve spends most of his time with Barnes, and it hurts, of course. But when he can, Steve steals into Tony’s bed (and/or workshop) and does his best to erase the pain, breathing fervent “I love you”s against his skin, and Tony tells himself to be grateful for what he gets. He was never going to be good enough to deserve all of Steve anyway. Even though he knows in his mind that this doesn’t change Steve’s feelings for him, he still thinks if he had any dignity he’d end it here and let them have their fairytale love, but he’s selfish, so he doesn’t. He wants Steve, and he’ll take what he can.
Apparently that includes caring about Bucky, which is unexpected, but Tony finds himself concerned about the assassin’s recovery for the simple reason that Steve is too. So he offers to help the only way he knows how.
The first few times Barnes comes down to the workshop Steve is there, hovering anxiously in the background as Tony and JARVIS run scans and create holographic models of the metal arm and then start designing an upgrade. Eventually, though, Steve just walks him to the door, and Tony gets the sense they’ve been talking. Bucky still doesn’t speak to the rest of the team, but Tony figures that doesn’t mean he can’t listen. So he chatters on as he works, explaining what he’s doing, bouncing new ideas off of him, and generally talking about anything that comes to mind. He’s not really sure if Barnes is paying attention until one day he glances up after having made a particularly witty remark to see a small amused smile on the man’s face, and Tony feels a swell of pride at having been the one to put it there.
Bucky spends less time attached at the hip to Steve, and starts coming to the workshop on his own. More than once Tony surfaces from an engineering binge in the middle of the night to find the ex-assassin curled up on the couch in the back of the shop sleeping lightly. He’s surprised to learn that Bucky comes to him as often as he goes to Steve when he wakes from a nightmare. One day, after Tony had gone several nights without sleep to finish up the latest thing for SI, Bucky brings him a cup of coffee. It turns out that not only was he paying attention, he remembers because Tony’s coffee is exactly the way he likes it, and he thinks through his under-caffeinated, sleep-deprived brain that he could kiss the man. That’s also the day Bucky speaks to him for the first time.
“Why?” he asks, and Tony puts down the pliers he’d been holding to look up at him.
He pulls down the collar of his tank top to reveal the blue glow of the arc reactor and the mass of scars around it. “This,” he says, tapping the metal in his chest, “is keeping me from dying. So I know how it feels to have this foreign thing suddenly invade your body, and how important it is to take possession of it and make it feel like a part of yourself. HYDRA gave you this arm as a weapon, but you can make it into whatever you choose.”
After that Bucky starts responding more to Tony’s chatter, until his word vomit starts to sound more like a conversation, and Tony discovers a personality snarky and charming by turns. Bucky starts speaking to the other members of the team too, and shows more initiative. He’s not afraid to express preferences and opinions anymore, and it turns out he has some pretty strong ones, mostly about food. He starts joining workouts, and cautiously tries out sparring with first Steve, then Natasha. Before they know it the days of the silent specter haunting the Tower are gone. Steve starts balancing his time more evenly between Bucky and Tony, and even takes Tony out on a couple of dates. So when Tony finds the two supersoldiers kissing on the balcony, he’s only a little surprised to find it doesn’t hurt all that much. Actually, he’s happy that Bucky has made it this far and that he still reciprocates Steve’s feelings. And if Steve is a little more passionate, a little more fierce in bed that night, Tony pretends not to know why.
The next day, while he’s putting the finishing touches on the arm, Bucky surprises him by saying, “Stevie says you gave him permission to kiss both of us. Didn’t think you were the type to share.”
Tony glances up because there’s no judgement in his tone, no hint of jealousy. He snaps the final plate back on and responds, “It just didn’t seem fair to make him choose when I know from experience he wouldn’t have been able to. Though I suppose if it’s going to work, you also have to be on board with him having both of us.”
Bucky slides off the table he’d been sitting on with a “hmm,” and there’s a tone in there that Tony can’t quite place. Suddenly they’re standing very close, and before he can take a step backwards Bucky takes hold of his hands and Tony realizes he hasn’t actually let go of Bucky’s metal one. That thought too is quickly wiped away because the space between them feels different somehow, charged.
“What if I don’t like the idea of Stevie having you all to himself,” Bucky murmurs and he’s right there, lips just barely brushing over Tony’s and Tony feels like suddenly there’s no air in his throat.
“That could work too,” he breathes before he’s pushing closer, pressing their mouths together firmly because holy shit he wants this, and how did he not realize sooner? Then they’re kissing for good, and Tony can feel metal fingers splayed against the small of his back and it feels so right.
When they break apart he can tell his grin is a little loopy as he says the only thing he can think of, which is, “Steve is going to be happy,” but he doesn’t care. (Steve would never admit such, but Tony knows pleasing both of them couldn’t have been easy.)
“Uh huh,” Bucky says, grin also at an adorably crazy tilt. “Let’s go ambush him with kisses.”
Which is exactly what they do, plopping down on either side of the unsuspecting supersoldier on the couch. Tony plucks the book out of his hands, tossing it on the coffee table as Bucky turns him by the jaw to kiss him. “Got something to show you,” he murmurs against Steve’s lips, and before Steve has a chance to respond, Tony is claiming his mouth for his own, whispering, “Think you’ll like it.” Then he’s pulling away and leaning across Steve to meet Bucky halfway for another kiss, which, as it turns out, Steve more than enjoys, if the small noise he makes when Bucky slides his tongue into Tony’s mouth is any indication. They pull back with a smirk and a wicked grin to find Steve’s pupils blown and his cheeks flushed bright red.
He makes a strangled noise that sounds like “You—” but doesn’t get any farther because Bucky is mouthing at his neck.
“We want this to be the three of us,” he murmurs. “All of us together, if that’s okay.”
“Yes,” Steve gets out in a rush, and Tony pushes his nose behind his ear, hiding his smile and wondering just what he did to deserve both of them.
He hums into Steve’s skin, pushing that train of thought aside because right now… “Right now I want it to be the three of us in my bed.” He nips lightly at the side of Steve’s ear.
Steve groans and tightens his arms around the both of them. “God yes.”