Tony finds out first, because of course he does. He doesn't understand how he could not have found out sooner. He regrets not finding out sooner. This is usually when Pepper slaps him.
It's after a mission, kind of a bad one, where Tony saved them all (like always, really, he does most of the work for this team) and Steve is yelling at him and he's snarking back. The rest of the team has wandered away because this has happened too often for them to be interested in sticking around anymore. Tony is privately glad because once Steve is done releasing his righteous rage, he releases other righteous things.
This is also when Pepper usually slaps him.
Except Pepper isn't here, and Steve is, but he actually looks kinda really mad so Tony doesn't want to test his limits right now. So instead he turns and marches into his penthouse, with Steve still shouting at him on his heels. And then Steve stops shouting. And Tony kind of stops breathing.
"What," Pepper asks him archly from where she's laying on the bed, underneath Natasha's heaving body. Tony doesn't really understand how she's so calm right now. He certainly isn't. He can feel Steve breaking down into a mess of confusion and sexual arousal behind him. Tony doesn't get why he isn't as well.
"Um," he says eloquently, "What?" Before he can break out into indistinguishable babbles Natasha flicks her head up and zeroes in on Tony. Tony shrinks.
"What," she repeats Pepper's dry tone, but her eyebrow is arched and she seems kind of amused so Tony doesn't have to worry about body parts being forcibly removed at least. He's still kind of not breathing though.
"What?" And yes, he can hear how high pitched and shrill his voice is right now. And no, it is not uncalled for. "Pepper?"
"Yes Tony," she says and it kind of confirms it for Tony, and his knees wobble.
"Nat?" He sounds slightly more incredulous. Honestly, he can't be blamed.
"Yes Tony," Pepper says again, and now she sounds very close slapping him so he shuts up. "You said they'd be occupied right now," Pepper says from the bed, and to Tony, Pepper sounds like she's whining but in a more sexy way Tony can never pull off that Steve always slants an unimpressed look at him for.
Natasha strokes Pepper's hair. "I know, I thought they would be. Steve's libido usually doesn't run out for hours."
And Tony knows Steve is bright red behind him because he starts stuttering, "W-What? Nat, what's going on?"
Natasha rolls her eyes and smoothly rises from the bed. "Boys," she says exasperatedly.
"Boys," Pepper repeats, but there's a note of laughter in her voice and Natasha's lips curve into a grin.
"They're lucky Maria isn't here too," Natasha says, heaving a dramatic sigh and cocking her hip. Tony's brain short circuits.
"Um," he says, and he stumbles backwards, "I'm pretty sure--- actually, I'm certain this is a hallucination or a concussion from that battle we just had, but um, I'm just gonna go." He slips back out the doorway. "Steve? You uh, you coming?"
Steve snaps out of whatever embarrassed trance he was in and trips after Tony. "Yeah," he says and shakes his head in disbelief. "Wait. Seriously? Nat and Pepper?"
"Don't forget Maria too," Tony says mostly to watch Steve's face turn purple.
Clint finds out next. Because Natasha has to tell him. He takes it as well as she could have hoped.
"Seriously?" He says with wide eyes. "Seriously?"
"Yes," Natasha says, and she allows him his moment of skepticism.
Clint whoops delightedly and grins. "That's---this is good, right? You're good with it?"
She loves him more because he didn't ask if she's happy. "Yes," she says, and she allows herself to smile with him because yes, this is good.
Bruce and Thor find out together. It happens just before dinner, when Thor comes home from a date with Jane (who is dodging Pepper's calls, and this is something Pepper knows is to do with Tony, and she's going to do some irreparable damage to that man one day she swears). He's lying on the couch in the communal living room and Bruce is cooking dinner in the kitchen, when he comes out and and unties his apron.
"Pepper?" He asks hesitantly, "Are you busy?"
Pepper likes Bruce, because sometimes he makes tea for Pepper and they sit together and bitch about Tony, which is one of Pepper's favourite pastimes.
"Not for you, Bruce," she closes her tablet and looks to him expectantly.
"I was just wondering---" he says, rushed, and rubs the back of his neck, "Um, you know how you and Tony--- well, you know how you are putting together that science convention?"
"Yes?" Pepper think she knows where this is going but she lets Bruce continue.
"Do you think--- maybe I could do a talk?" His voice quietens and he's flushed bright red and he looks ready to bolt. "Just, just a small one, on immune diseases, because I conducted this really interesting experiment yesterday, actually Tony helped me with it maybe he told you about it but, okay I separated a strain of---"
"Bruce," she interrupts him, laughing slightly, "Bruce, calm down, of course you can do a talk."
He looks up with a hopeful smile. "Really?"
"Yes, yes of course," Pepper assures him, "I have an empty slot, well, not empty but Tony doesn't even like Reed so I'll cut his time down, so there's space after Jane so you can slide in there---"
"Jane?" Thor is roused from his rest and looks attentively at Pepper. "What of my great love?"
Pepper hides a smile behind her hair. "Nothing Thor, me and Bruce were just discussing the science convention Jane's speaking at."
Thor's eyes sparkle. "Ah, yes, the talks about the understandings of how Midgard functions, yes, I recall Jane speaking to me about it. She is most intelligent."
"She is," Bruce agrees with Thor solemnly, then he smiles at Pepper. "And thank you Pepper."
"Not a problem," Pepper says to him.
Bruce rubs his hands together. "Alright, dinner should be ready now, I'll call Tony and Steve up from the lab."
"Is it okay if Maria joins us?" Pepper remembers, and Bruce gets a slightly confused frown on his face.
"Yeah," he says, "But why is she in the---" he cuts off as Thor leaps from the couch and jostles him. As Thor attempts to apologize by righting Bruce's glasses, Bruce says, his voice muffled, "I think Clint is with Natasha sparring so---"
"Clint isn't with Nat," Pepper says to him, and smirks privately. Bruce raises his eyebrows at the nickname but doesn't comment. Thor, however, does.
"Ah!" He exclaims. "Lady Pepper! I had wondered of your relationship to the great warriors Natasha and Maria but I had not thought of this! Congratulations are in order!"
Bruce blinks and Pepper inclines her head in thanks. "You're right Thor," she says wryly, "Congratulations are in order. Maybe dinner?"
And then it clicks for Bruce and his eyes widen but a smile slides onto his face. "Yeah," he says, and grabs his apron, "Yeah, definitely. Dinner." He turns to Pepper. "Tony?" He asks, humor lacing his voice.
"He took it as best he could," she tells him, "But it helps that Steve is with him to soften the blow to his ego."
Thor laughs uproariously and Bruce's eyes get even wider.
Coulson finds out on his own. Maria doesn't begrudge him. If she's being honest with herself, they weren't trying to be subtle.
After a meeting about the helicarrier's security, Coulson walks up to her and raises a single eyebrow.
Maria doesn't look at him and continues packing away her files but she knows he knows and her attempts to ignore him will prove fruitless. "Yes," she says, and its not an affirmation because Coulson doesn't need that but it is a confirmation of what everyone suspects.
"Okay," he replies, and leaves the room. Maria finishes packing up.
Fury already knows. It's kind of overshadowed by the fact that he's screaming at Steve and Tony because he knew about the girls, but not the boys. Bruce tries not to find this funny.
Tony stands there taking it with his arms crossed, and Steve stands next to him, upright and the very picture of staunch patriotism that isn't exactly the original American Dream.
When Fury is finally done ranting Steve looks kind of happy and Tony is pouting. Fury swivels his eye over to Natasha and squints.
"Romanov---" he starts. She smiles at him and he sighs. "Keep it under control."
"Yes sir," she says obediently, and Tony gapes at her from across the room.
"How come she doesn't get yelled at?" He complains. Steve pats his arm.
Fury rolls his eye. "Do I really need to answer that question?"
Tony glares at Fury but Steve tugs him closer and he grins into Steve's shoulder.