All I remember is that Steve and Tony are dating, but they are also dating Bucky? Or Clint? Or someone else. Can't really remember. But no one on the team knows this. So when someone walks in on two of them together, the person that walks in assume one of them is cheating. I don't remember if it was Steve or Tony that were accused of cheating, or if I am mixing some fics here.
But either way, I would be really happy with any fic like that.
Where Tony is in a threesome, and the rest of the avengers have no clue, or it can be Pepper that doesn't know. And one of the threesome is accused of cheating. Or Tony is told to leave Steve and Bucky alone.
Thank you in advance!