Spread across several episodes Ben and Adam have been following the breadcrumbs of the "real" Miles O'Brien who lives in a loveless marriage to Keiko.
TNG Season 4 Episode 11 (Data's Day): O'Brien seems to be in an arranged loveless marriage to Keiko ... the beginning.
TNG Season 4 Episode 12 (The Wounded): O'Brien and Keiko, having just married, have an argument about breakfast. Neither of them know what the other likes.
TNG Season 5 Episode 15 (Power Play): O'Brien is "possessed" by an alien and holds Keiko and their daughter hostage.
TNG Season 6 Episode 2 (Realm of Fear): O'Brien keeps a poisonous spider as a pet while living with an infant.
DS9 Season 1 Episode 3 (Past Prologue): Keiko seems surprised that she and O'Brien are on DS9, as if there had been no previous discussion about it.
DS9 Season 1 Episode 4 (Babel): O'Brien is close to death in the infirmary but Keiko never visits and is seemingly unaware of his plight.