So. The OTP challenge has a prompt that’s “Get into an argument” followed by “They make up”
This isn’t either but here’s what happens. Ty shows up. Steve finally puts together how many exes Tony has had as well as one nighters. It wasn’t really a secret but it just sorta clicks in Steve’s head.. And he’s not happy. So they fight over it. And Tony leaves.
He’s staying with Ty because Ty is a manipulative bastard and Tony’s staying with him before he even really realizes it. Given the chance he would have stayed with Rhodey obviously.
And Ty is a total creep and enjoying the fight because that’s KIND OF WHAT HE DOES. And this is him harassing Steve.
(Tony’s asleep in the photo and Ty probably took his pants off for the photo and because he’s a creep)