The Wedding of Superman and Lois Lane
This is not a dream, a hallucination or an imaginary story.
The events here deal with the Superman of Earth-Two.
Colonel Future and his C-F Gang recruit The Wizard to perform the greatest disappearing act he's ever done - making Superman disappear. While that has the intended effect for them - a world they can loot (nearly) unopposed, it has another unintended effect for Clark Kent. Free of his obligations as Superman, he can and does marry the woman he's always loved, Lois Lane.
This is a fine 40th Anniversary issue. The creators keep Earth Two distinctive by imitating the Golden Age style without losing the refinements of modern storytelling and art. For Curt Swan this means imitating his own earlier work on Superman, and he does it well. The story could have come off like retro-cheese, but instead it comes off as quaint and heartwarming, without becoming predictable.
And best of all (not really a spoiler anymore), even after the story's resolution, and the return of Superman, the couple remain married!