The answer to the question, who cheated on my TwiSentry ship is………… both, they both did it. Each of them had their own reason, but lets begin from the… beginning…
 
Twilight and Flash had a really happy live together, so happy they decided to have a child, they were so happy Twilight happened to get pregnant a second time unexpectedly. They were a really happy family. But sometimes life is hard and I love drama.
 
The two little ones had a really tiny accident where both of them got injured, one fisically the other mentally. The older one got really traumaticed about what happened, the youger one could have lost the integrity of her body. The constant care both of them needed affected their parents’ relationship. While both of them had a really important job to do, Flash decided to take care of his children just so his wife could keep caring about her duties as a princess. Twilight wanted to take care of her children by herself, quit her duties as princess and spend 24 hours per day to them, but she was too scared, she could hurt Heather, she could make Ceres’ condition worst. Twilight was frightened her action could make their children get seriously hurt in anyway.
 
Flash’s days without sleeping and Twilight’s everyday more visible depression affected them, bad things were said, things that in a normal situation they’d talk as adults and probably wouldd ended perfectly okay, but not this time. Flash was called to Canterlot for a really important job, he could have say he had to take care of his children, but he couldn’t see Twilight’s for anysecond more. It hurt him. She used to be an energetic and passionate pony, reduced to a shadow of what she used to be. He was not sane either. It was meant to be this way.
 
When Flash left, Twilight tried really hard to take care of her children by herself, but she wasn’t strong enough, Ceres’ wouldn’t get better and Heather seemed to change from a really smiling filly to a silent observant filly. Thankfully Starlight was there to help, she was there to hel her. Finally a shoulder to cry on.
 
Twilight was so scared, so tired, so alone, so desperate… she felt onto the purple pony’s arms.
 
Flash was really angry, really tired, really lonely, really desperate… his body moved all by itself.
 
None of them are happy or proud about what happened. They both took it to the end. They both regret it. Two of them were not careful enough.
 
But maybe not everything is lost. A new life was made, and a really strong relationship was reborn.