As of season 1, episode 15, it's confirmed that he'd been working at PPTH for eight years, which means the first three years working there he was still with Stacy, but Cuddy is once quoted as saying that he's taking "twice as much [Vicodin] as when [she] hired [him]," which, hopefully at that time, should have been none.

Just a random nitpick I saw a window to complain about. Sorry. :x