Celestia and Luna married the mane six, now they have a harem and a honeymoon to deal with. In all honesty, happily ever after isn't all it's cracked up to be. At least there'll be room for orgies.
When the effects of an injury prove more severe than first thought, Rarity and Rainbow Dash find themselves struggling to keep their newfound relationship and lives afloat.
Nightmare Moon must come first in your heart. Always. To betray one's devotion to Her Majesty with love for another is an act of high treason: a Heartcrime. Night Chamberlain Rarity's sure she's not a criminal. But she's been wrong before.
Rarity needs a live model to practice her rusty drawing skills. Rainbow Dash is the perfect pony for the job. Now if only Rarity didn't find Rainbow's posing so provocative ...
Realizing that her love life was a horrible disaster, Rarity thinks that she is maybe looking for love in the wrong place. Rarity finds that one of her friends has certain qualities she finds desirable and that she may have romantic feelings for her.
Rainbow Dash definitely didn't do anything wrong. Rarity is the one who's wrong. Rainbow Dash is absolutely, totally, a hundred percent sure of it. But then why did she just buy a wagon load of apology bouquets?
Applejack and Rainbow Dash ended up together in the main universe - through the portal, it was Applejack and Rarity. It's a fair question who made the right choice - from the sidelines, the other Rainbow and Rarity wonder if it was them.