Tony shouldn't be looking. He knows that. But there was something about them, something that pulled him to them like a magnet. Something he couldn't fully explain.

Maybe it was just because all the soulpairs he had seen in his life never really worked out. His mother and father were soulmates and yet they had drifted apart. As much as he would like to believe, the reality is that 'soulmates' were fair from the romantic fairytale people always hyped it up to be.

But Steve and Bucky had been together for over ninety years. Granted, seventy of those years were spent apart. But despite all that, despite what the world had thrown their way, they were still going strong. They were the perfect image of soulmates in love.

He liked to think it was curiosity, sheer wonder at how they managed to keep their relationship going strong after all those long years. Deep down a part of him knows it's equally longing. Deep down, he wanted to believe in all those fairytale fantasies. He wanted to find that special someone who would complete him, balance him out. Someone to love and be loved by in turn. Deep down, despite telling himself it wasn't true, that those things never happened, that it was all stories told to children, deep down a part of him still wanted to believe it could be true.

Tony watches as Steve and Bucky kiss under the spray of the communal showers, sharing such comfortable casual touches. His heart aches with longing, with a desperate hope that he could find that someday.

He watches as long as he dares. Soaking in every touch the gift one another. Wondering, what it would be like if someone touched him like that. Held him close, as if he was something precious.

His stomach twists, knowing that he shouldn't be staring. It was wrong, creepy. But he couldn't stop himself. Next time, he tells himself, he would use his private shower in the penthouse.

Steve laughs at something Bucky whispers to him. Before Tony can let himself wonder what the man had said, they both shift, exposing the soulmark that rest's on Bucky's inner thigh.

There is nothing he can do to stop the gasp of shock that is pulled from his lips. Soulmarks are intensely private things, shared only with your soulmate. He had never seen Steve or Bucky's mark, but he knows it intimately. He has the same mark on his own thigh.

But that can't be right. Steve and Bucky were soulmates.

…Weren't they?

Steve and Bucky turn and stare at him, covering themselves. "Tony, you okay?" Steve asks softly, concern written all over his face.

"Your mark…" Tony says.

Bucky and Steve share a look, both looking a little confused and uncomfortable. "What of it?" Bucky asks.

He had to be wrong. There was no way. It was an impossibility. "It's nothing. I should go" he says. He turns off the shower and quickly heads for the door.

A hand on his shoulder stops him. He turns around to see Steve standing right behind him. "It doesn't sound like 'nothin'," Steve says. "What's up?"

"Look," he says, shrugging Steve's hand off his shoulder. "I have things I need to do. Given that I pay all the bills around here, being the only one with a day-job"

He steps back from them, meaning to turn around and leave.

"That's…" "No…" The two men gasp at once.

"What?" he snaps, folding his arms over his chest protectively? "Look, I really don't have the time for this"

"That… That's our mark…" Steve says, pointing to Tony's mark.

A well of hope floods his chest. Could it be? Could he really be so lucky? "It is?" Tony whispers.

"I'm pretty damn sure of it," Steve says softly, slowly approaching.

Steve pulls Tony into his arms and presses a kiss into his hair. Bucky comes up behind them and envelops them both into his arms.

"So just like that, you are just going to accept I'm your soulmate?" Tony says into Steve's shoulder.

Steve shrugs. "You learn not to question these things. Makes life easier, really. "

"Okay then," Tony says, smiling.

Maybe he could let himself believe those stories after all.


The End

Notes: In response to a prompt by Fearlesslexi in the stuckony_summer_stocking_2020 collection.

Inspired by the prompt: soulmate au