"… Tony and you have been woven together since before the two of you were even born- since before the birth of the first human child, I’m guessing, if what I’ve heard is true. Your bond is deeper than gold twine, deeper than white."
"Um," Steve says, but apparently Sif isn’t finished.
"It is- it is not just destined, Steve Rogers. It will reach through the decades, through entire universes if it has to. It will scour the galaxies without rest until the two of you are standing next to each other. Migardians-"
And there it is again, the tiny mouth-twitch, looking up at their faces like she’s breathing the both of them in. “Migardians call them soulmates, I believe.”
"So," Steve says, and Tony doesn’t startle, but it’s a close call. "Soulmates."
It’s then that Tony realizes that no, they haven’t, in fact, had this conversation yet.
“In every universe,” Steve continues, like he’s telling him what he wants for breakfast.
Tony says, “Seems like,” and for a split second, he thinks the string tightens.