Sure, he moved to a new city on a whim, but he's an eccentric billionaire - that's allowed!
And sure, he moved from a massive compound, mansion, and tower, to a tiny little one bed apartment that barely has enough room for him - it was cosy!
And sure, he barely sees his friends and does nothing but work - his job right now is important, okay? He's got to fix the accords and bring the Avengers back, for the safety of the planet!
Tony Stark is fine. This is not a mental breakdown.
Tony slams his hands angrily on the surface of Howard’s workstation, making everything tremble until his father glares furiously at him. He ignores it and begs, “Please don’t make me marry my godfather.”
Or
Yet another Marriage of Convenience AU with a/b/o dynamics that no one asked for. Angst with Happy Ending™ 100% Guaranteed or Your Money Back. This has an extremely experimental and dramatic tone that shifts unexpectedly at times.