As fate would have it, it turned out shortly after Tony made his resolution that Steve was called out on a mission. He would probably be gone for a little over a week.

The fit he threw upon hearing the news wasn't exactly minor but no one seemed to bat an eye about it. For his part, Tony wasn't sure if he was more angry about the fact that he would probably lose his nerve by the time Steve got back or the fact that he wasn't going to get to see the other man for an extended period of time.

His alpha instincts made him antsy as he considered the fact that Steve could be in danger and he'd have no idea and would be unable to protect him. He was also worried that Steve could potentially find an omega of his own, bed them, and come back mated. Though he he refused to acknowledge that that was a real feeling he was having. Honestly, that seemed a little far fetched, but how could he argue with his instincts when they demanded he assert himself over what they seemed to feel was meant to be his?

oOo

Sure enough, almost two weeks went by. Two weeks without a single word from the super soldier. Tony thought it odd, Steve was usually very good about checking in with the team once every few days at least. Perhaps the mission required a greater amount of stealth than usual, there was no way to tell. S.H.I.E.L.D wouldn't tell him anything. In any case, by the time Steve had returned Tony's resolve had wavered. He said nothing of value when the exhausted blond strolled back in, covered in some sort of grime and looking like hell..

Tony observed him from the couch of the common room. He watched the way the blond limped just a little, favouring his left leg, and swept his gaze over the whole of him in search of any other serious injury. Or maybe bite marks, whatever. Satisfied when he saw nothing he settled back, visibly relaxing.

He wouldn't admit it but his heart did race a little over the way Steve looked like pure sex in the torn Captain America suit he wore, the way his hair hung into his eyes. He couldn't stop the pleased little purring rumble in his throat.

It was then that the blond caught sight of him sitting in the corner and froze. Did Tony just growl at him? He turned around quickly to use the long hallway instead of crossing the common room floor for fear of disturbing Tony further.

"Hey, Spangles. Welcome back." Tony said abruptly. Steve faltered briefly before offering a smile and nodding in acknowledgement with a polite 'thank you.' He hesitated and then decided it would be rude to turn and leave now, so he crossed the floor.

When he passed by, distinctly avoiding eye contact and moving quickly so Tony couldn't stop him again, Tony caught a whiff of the pheromones on him. His entire body immediately went rigid. It was something unfamiliar though somehow rustic, a scent he'd never detected on Steve before. Something distinctly omega but subtle. Like the pheromones of an omega at the tail end of their heat. Before he could stop himself Tony had caught Steve by the arm and held him in a bruising grip so he couldn't shake him off too easily.

"Have a good time?" he snapped, crowding into his space.

Steve stepped back, obviously confused. He glanced down at Tony's hand and then back up into his eyes as his back collided with the wall. Steve's hand landed on top of his and pushed it away just enough to be able to step out of his grasp along the wall. Tony followed step for step.

"W-wha? N-no, not really? It was work, I–"

"Hard work, huh? Yeah, I guess it's a long, hard day when you're pounding–"

"Tony!" Steve gasped, scandalized.

"–the pavement. Don't give me the good little Church-boy routine, Rogers. Who'd you meet up with? Where'd you go? What's their name, Steve, you might as well just tell me. I can smell you, you know. You reek of dirty omega slut, so you couldn't have been working too hard."

With every question he snarled Tony found himself closer in Steve's space, backing the latter along the wall and approaching a corner. Steve's face turned bright red but his eyes never stopped moving. Tony could see him mapping escape routes over his shoulder.

"I wasn't with anyone. What the hell is this all about, Stark?"

Despite himself, Tony found himself inclined to believe him. But there were distinct pheromones in the air and how could his nose deceive him? Steve's voice had all the conviction in the world but the look on his face said he had something to hide. He rolled his shoulders, forced himself to step back, and let the Captain go.

"Fuck," he breathed. "You know what, fine. Nevermind. Just get out."

He wasn't expecting Steve to grab him by the collar. "Oh, no you don't! You can't expect me to just let all of that go? What the hell is the matter with you?"

"Great, so now you want to talk to me, is that it!? What's the matter with me? YOU!" Tony cringed at how hurt he sounded to his own ears but it was already coming out. He was shouting in Steve's face. It was utterly beyond his control. Steve's blue, blue eyes and wide blown pupils stared into him but all it did was cause a stabbing ache in his chest that reverberated through the rest of his body. Tony's hands went numb. His skin burned. "Isn't that great, just fantastic, that I'm suddenly worth your time again? Why don't you just tell me, then, why the hell did you just stop talking to me? I can't figure it out, what the hell did I do to you, what the fuck do you want from me, Steve!?"

"What?" Steve was so confused. It was written all over his face. Tony couldn't blame him, he supposed. But those pheromones hung in the air between them and every time he breathed in he wished his lungs would collapse.

"I gave you the space, I guess, because I thought you wanted it. Because what the hell else could I do? Figured you'd sort out whatever and then we could– And now you've– Fuck!"

Tony quickly recovered himself. He slipped back into that impenetrable mask and backtracked rapidly. This was so, so stupid. He couldn't believe he thought this could have gone any other way. Steve searched his eyes, but it hurt. He needed an out.

"Nevermind," he snarled decidedly. "I can't fucking stand you. Get your hands off me, let go. Before I get the suit, I swear to God, Steve– Maybe you should save everyone the trouble and just fucking leave."

He wasn't sure what he did expect, but Tony did not expect Steve's mouth to snap shut at that. He did not expect Steve's jaw to tighten or for his eyes to get so red. He did not expect it when Steve practically threw him away by the collar, as if he'd been physically burned by touching him. He did not expect it when Steve murmured a quiet apology before leaving, followed by the resounding slam of a door somewhere down the hallway. He did not expect how badly it felt to push the former soldier away. It wasn't as though he hadn't done it with countless other people before.

Tony suddenly felt sick to his stomach. His knees felt as though they were going to collapse under his own weight. Suddenly he was seated on the couch again, his chest practically on fire. He craved a drink. The silence was deafening, his head throbbed. He jumped when the other door to the room opened.

Natasha and Clint peered around the doorway looking for the source of the dispute. The redheaded alpha and the sharpshooting beta had evidently heard the whole thing, or at least a great deal of it. The cautious looks on their faces were indicative of that fact without doubt.

Nat approached Tony slowly and laid her hand on his shoulder, motioning for Clint to shut the common room door behind them. Tony's hands itched painfully but he didn't want to touch anything with them. He wanted Natasha's warm hand off of him, too, but he couldn't find the words. His mouth tasted of bile. Natasha didn't move or say anything, and neither did he. What could he say?

The thought of Steve with someone else, someone else's scent sticking to Steve's body, had completely set him off. Confronting Steve wasn't supposed to be like that. It was supposed to result in a mutual understanding that could potentially lead to the culmination of a healthy relationship between the two, clashing alpha instincts be damned. He wanted to be gentle with Steve, to tell Steve he loved him and for the love of whatever deity was out there he wanted Steve to love him back. But this time he couldn't even blame his genealogy for his problems, he fucked this one up all on his own.

oOo

Steve had made a full escape and managed to put two sets of doors between them before he felt himself let go of his tight facade and sob loudly just once before putting a cap on it. Well, at least he finally had an answer for why Tony always seemed so agitated when he was around. Apparently he just fucking hated him– great. Half of what the brunet had said hadn't even made any sense, but that didn't change the final message.

'Just fucking leave.'

Steve's arm burned where Tony had touched him. His skin crawled, his heart pounded, from having a dominating alpha-type get so close into his space so soon after a heat cycle.

He had taken a week off to take care of himself to avoid something like this happening but he had evidently come back too early if Tony could still smell the remnants of his heat on him. His heart hurt, knowing now for certain that Tony thought the mutated pheromones on him were disgusting.

Anger, confusion, and self-loathing swirled in his chest until he could barely breathe any longer. "Goddamnit...!" Steve cried, slamming a fist against the wall. The plaster shattered under the force of the impact.

He stared at the cracks under his fist for a moment, horrified by what he'd done before the feeling drained out of him and his other fist launched to land just above the first.

At this point, honestly, who cared? Tony already hated him anyways.

He went back to his room and changed out of the torn suit he had put on as a part of the 'mission deception.' He took in the furniture. Most of it belonged to Tony. It was nice furniture with a vaguely forties style. Most of them were expensive solid oak near-antiques that had been purchased for the sole purpose making him feel more comfortable in a building that was largely technological. Steve didn't know for sure whether or not that was Tony's doing or Pepper's, but he had been deeply touched by the effort they'd put forward. Now, though, he was concerned it had been a huge burden to put together. The thought made him sick. Stark had truly done everything for him, and he'd had the nerve to want more. To want Tony himself. He had entertained feelings he'd had no right to feel, and it turned out that Tony had felt the complete opposite anyways. Served him right.

The furniture all belonged to Tony, but most of the clothing in the wardrobes was his. He grabbed anything that belonged to him and stuffed it inside a bag he'd used for travel that he left under the bed. He was fairly certain it was Tony's too, but he could always send it back when he found an apartment. S.H.I.E.L.D might agree to put him up for a while if he could get in direct contact with Fury.

Everything he needed fit easily into the one bag, even without being folded neatly. Especially since he'd decided to leave behind everything Stark had purchased directly for him and anything he knew he could do without. He had some sketchbooks and art supplies that he had accumulated over the past few months, but he would get the rest of that stuff later. It was too much to carry out for now.

He thought about leaving a note, but decided that ultimately was too much of an ex-lover cliche. He would just leave quietly, like Tony said he wanted him to. His eyes stung painfully as he lifted the whole bag so he wouldn't make any noise by dragging the wheels along behind him. He wanted to make his escape without running into anyone else.

Steve took the long hallway around the common room for fear of the genius still being there. Somehow he still ended up running into Natasha.

He didn't know why he thought he could get away with leaving without a word.

"You know Stark didn't mean any of that," she said, keeping up with his fast paced stride. He tried not to be annoyed. She could catch up with him, but she couldn't make him stop.

"No ma'am, I don't know that. He sounded pretty serious to me and that's just fine. I can handle living alone, I did it before."

The look she gave him was withering. He purposefully avoided eye contact. He wasn't sure how he would handle it if he had to look at her glare head-on. He silently jammed his thumb into the elevator button when they came to it. "Steve, stop it. The two of you are just ridiculous! If you just told him– don't give me that look! If you just told him the truth that argument wouldn't have even happened. Don't you understand what happened in there? He's–"

"No. No, no. I definitely can't tell him now. He smelled me and was actually disgusted by me, by these fucked up genes I have. He called me a slut, Nat. He hates me."

"Steve, please shut up for just a second. I'm trying to tell you that's not what he meant!"

"It sure sounded like he meant it to me!" he snapped. "Look, I appreciate what you're trying to do but it's not like you'll never see me again, Nat. I'll contact you when I know where I'll be, okay?" Steve kissed her cheek and ignored her protests as he slipped inside the elevator. It closed, finally separating them.

Steve immediately collapsed to his knees after being hit full-force by a wave of exhaustion.

How the hell did things end up this way?