Every child is born with two marks, one from their mother and one from their father. They say that each mark represents a lesson your soulmates will teach you, that you can gain more and more as you go through life.
Tony was born with four. They said he was destined for greatness. If this is what greatness looks like then Tony doesn't want it.
In an alternate universe, Tony Stark never came out as Iron Man, even to his teammates. Sometime after CA:WS, Bucky comes to the tower, regains his memory, and rekindles his relationship with Steve.
A year later, Steve and Bucky realize neither of them have ever had sex with anyone else, and they probably won’t if they keep their relationship monogamous. When they decide they want to explore, Bucky decides to ask Tony for a one night stand, and Steve decides to ask Iron Man. Both of them bite off more than they can chew, as they both discover that they’re in love with their extracurricular lover - while still being madly in love with each other. Tony just hopes it’s all worth it, because if they ever find out it was him with both of them, he’s pretty sure they’ll never want to see him again.
Tony likes to think he doesn't lie to himself, if not the rest of the world. So he knows that his insecurities are pretty much as textbook as they get. Abusive father, absent mother, misunderstood by his peers, almost murdered by that asshole. Yeah, it's pretty obvious why he shies away from emotional fucking honesty with anyone other than, you know, Pepper. That one time. Which had just such a great ending. Ugh.
When he finally gets over himself and accepts that Steve might be good, might be a good thing, a thing that he could possibly maybe actually deserve here, it should surprise him that Bucky fucking Barnes is recovered. It doesn't.
"I will give you two hundred dollars if you hide me until my asshole ex leaves." The bartender blinked in surprise and reached towards Tony again. His panic spiked. "A thousand plus whatever I have in my wallet. Anything you want. Please."