After a discussion with Lightning Dust, Dash realizes how much freedom she's given up to have a family with Pinkie and Scootaloo. So, why is she so happy?

(Ties in to The Marriage of Heaven and Earth and the Care and Raising of Pegasii, but reading those two aren't strictly necessary for enjoying this one).

Pinkie will sit and wait right by the mailbox until she gets a letter from that marefriend of her's. After all she did promise to write to her, she always keeps her promises. If that the case, then why Pinkie heart breaks bit by bit everyday.