This is the story about the Apple mare and the Pie mare

Applejack Pear is the Daughter of King Bright Mac the Unicorn and Queen Pear Butter the Pegasus and the mate of Pinkie Pie the Party mare and the Mother of Shake Apple and the rival of Flam the Apple stallion
And falls in love with Pinkie Pie.
And Pinkie Pie is the adoptive daughter of Mister Cake the Pie stallion and Miss Cake the Muffin mare and the mate of Applejack the Apple mare and the Mother of Cake Blossom and the rival of Cheese the Party
Stallion and falls in love with Applejack.