The next day he was in a tank top in his lab when Bruce dropped by.
"Sup Brucie?" he greeted, waving a wrench at him.
Bruce stopped where he was, and blinked at him. "Tony, what did you do to your arm?"
Tony glanced down. He'd forgotten about it. The bruise was dark and prominent, standing out on the pale skin of his upper arm.
And it was clearly a handprint.
Tony swallowed. "Okay, so I know how this looks-" he began.
"Did Steve do that to you? Clint told me you had a fight yesterday, but I didn't think it was that bad."
"It really wasn't," he protested. "It was an accident"
"Tony," Bruce warned.
Tony rolled his eyes. "You weren't there, okay? You know how he gets, all Super Soldier-y. He really doesn't know how strong he is. It's not his fault. I shouldn't have provoked him."
Bruce let out a sigh that was more of a growl.
Tony examined his eyes for signs of green. "Whoa, don't hulk out on me now. I'm a big boy. I can take care of it. It was an accident, and it sure as hell won't happen again."
Bruce's eye flashed dark, but he didn't grow or transform, and after a few deep breaths, he nodded.
"Tony, if anything like this happens again, I will not hesitate. Now, you are going to come with me and get it examined. And x-rayed, because I worry."
Tony knew there was no getting out of that. He get his tools down and sighed, trailing after his science bro.
"A fracture?" Tony repeated, not believing what Bruce told him.
"Just a hairline fracture, but yes," Bruce told him, tracing the thin line on the x-ray that Jarvis had displayed.
"Oh," he said dumbly. "Won't need surgery though, right?"
Bruce shook his head, no doubt keeping his emotions barely in check.
"Sling and immobilization for a while though," he said flatly. "Did you honestly not notice it?"
"Yeah, about that," Tony muttered, scratching his head with his non-broken arm. Bruce was already adjusting the sling to his arm.
Bruce looked up at him as he trailed off. "What?"
"Have you heard of CIPA?" Tony asked quietly. "Congenital insensitivity to pain with anhidrosis."
Bruce's eyes widened. "Tony, do you..."
"Well, technically I have congenital insensitivity to pain with partial anhidrosis, which is good, because I do sweat, which means I'm a lot less likely to just sort of die in my sleep or something, because I won't overheat."
Tony knew he talked a lot when he was nervous, not that he would admit it, being nervous that is, and couldn't seem to make himself shut up.
Bruce had finished fiddling with Tony's arm, and sat down in a spinny chair across from him.
"It was sort of nice for the surgery in the cave, you know, no anaesthetic or pain meds, but Yinsen wasn't really happy because how are you supposed to know about complications if you can't feel them? So yeah, it's kind of an issue with fights and everything, but I have Jarvis for that, which is good. Coping mechanisms and all that."
He shrugged, before realizing he shouldn't do that.
Bruce blinked at him. "Wow," he whispered.
Tony examined him. He didn't seem angry, but then if he was really angry, he'd be at least three times as big, as well as green by now. So not looking angry didn't mean anything when it came to Bruce.
He ran over what he'd just told Bruce. Apparently he told him about Yinsen and what happened in the cave. Huh.
And maybe it wasn't angry that Bruce was looking at him with, but understanding, and maybe even some pity in there, which wasn't okay.
Tony scratched his head again, resisting the urge to stretch in his discomfort. "Um... yeah. So there's that. I kind of haven't told anyone else. I mean, Natasha probably knows, because there was that whole time when she my pretending to be my assistant, and was actually spying on me for SHIELD. She probably knows because Fury probably knows, since it kind of is a matter of record, not public record, mind, my father would have taken care of that, but still." He shrugged, despite knowing a split second later that he shouldn't have. "There's always a trace somewhere."
Bruce blinked at him, and Tony was very careful to not make eye contact, staring instead at the x-ray that was still displayed behind him.
"So... Steve doesn't know?" he clarified, after a long moment of silence.
"Um, no, that's what I just said, weren't you listening?"
"Tony," Bruce said, placing a hand on Tony's shoulder, and he totally didn't jump, because he was stronger than that. "It's something he should know."
Tony scowled. "I know that, of course I do, I'm a genius, remember? But that doesn't change the fact that I just really don't want to tell him. Cause then he'd been all concerned about fights and stuff and be even more super protective than he already is, and I don't need that Bruce, you know I don't," he pleaded.
Bruce nodded. "I suppose you do have the suit," he said slowly. "And Jarvis. I'd have to talk to him about the protocols before I feel comfortable with the whole thing, but seeing as how you've been doing this for a while already, I don't see how I can really have a say."
Tony beamed. "Damn right. Steve doesn't need to know, because hello, I haven't died in a fight yet. I'll be fine, just like I always am." Bruce didn't look entirely appeased. Tony raised an eyebrow. "Brucie... what's the issue?"
Bruce blushed, and stammered the words out. "But what if he hurts you... other times? You know..." he made a vague hand gesture, and it was adorable to watch him being so flustered until it hit Tony what he was trying to say.
"Bruce?" Tony asked, his mouth gaping halfway open. "Do you think Steve and I are fucking?"
Bruce blushed violently. "Um, well, the general consensus among the rest of the team..." he trailed off. "Mostly Natasha," he corrected. "She was the one who confirmed it, or at least we thought so. But she knows things, her and Clint, and we had no reason not to trust her..." he trailed off. "Crap," he sighed. "Clint won the betting pool." He looked up at Tony. "Yes, everyone thinks you and Steve are in a relationship."
Tony flung whatever was nearest his good arm across the room. It turned out to be Bruce's phone.
"I'll fix that," he said quietly. "No, I'll make you a new better one that can't break. Did it break? Probably not. Genius." He sighed, slouching back in his chair. "Everyone?" he repeated.
Bruce nodded miserably.
Tony sat up, an idea startling him. "Oh Bruce, don't tell me that you thought Steve was hitting me?" he demanded. "Is that what you thought this was from?" he added, gesturing to his arm.
Bruce blushed again, and didn't reply.
Tony sighed, returning to his slouched position. "Well, thanks for being concerned about me," he said finally. "Even if you jumped to a conclusion without all the variables."
Bruce nodded. "I'm sorry," he mumbled. "About that, and about the rest of the team thinking..." he waved his arm in the air.
"Not your fault," Tony assured him. "How much did Clint get?"
"Oh, we didn't bet money," Bruce told him.
When Bruce told him what they used instead, Tony nearly fell out of his chair laughing.