The prompt: She’s just a rambling mare.
"I don't know what happened, but you've changed. I'm getting really sick of this."
There it was.
That flicker of doubt in his eyes, that momentary drop in the sustaining flow of his love for his 'wife'. That's how it always started. Even when she was being overfed, even when she was doing everything she could to suppress her natural superiority and act the part of a loving pony wife, this always happened at some point.
Chrysalis kept up appearances, of course. She tried to keep the argument low-key, she kept herself from snapping at the stallion, suppressed the urge to just blast his stupid pony face with magic. It wasn't easy, despite her unending years of practice. She could keep up the conversation without thinking, now, which left her to ruminate on all her previous failures. Not that it always ended this way, even if the pony she fed from always ended up with doubts. Sometimes they'd last until the feeding killed them, and she'd call it a success and move on. Sometimes it was like this, a rising tide of doubt until she had to leave under threat of discovery. Sometimes, well, sometimes the replaced pony could be found, and she and her swarm would be driven from Canterlot by some unbelievable magical explosion.
Sometimes.
"What? Are you saying we should get a divorce?"
She spoke the word, and she got the intended effect. She could feel his panic at the idea, a hollow tang on top of his love. This stallion was nopony special. He wasn't a prince, or a soon-to-be prince. He wasn't a mayor, or anyone of any personal power. Just a farmer, in Appleloosa. His love tasted much like most of his ilk. Simple, honest. He backed away from his outrage and his doubts immediately, doing anything he could to avoid the dreaded 'd' word. But that crack in the facade was still there, and she knew it would only grow.
The dinner date went on. The fight was over, even if she could sense the tension under his smile, changeling empathy not even needed. They ate together, they drank wine, they talked of the boring mundanities of a small town like Appleloosa. They did not discuss the closed down coal mines just outside of town, thankfully, as reopening those may lead to the discovery of this stallion's original wife. But drones here and there in the town council kept the place closed, and presently the dinner ended and they strolled through the streets of Appleloosa.
Chrysalis couldn't help but wonder how long it would take to drop the rural twang that had crept into her voice over the course of this charade.
He'd forgotten the argument by now, almost. The three-quarters of a bottle of wine, as well as the good food and... well, forcedly pleasant company, had lulled him into a typical pony-like loving stupor.
As they walked, she caught the eye of her subjects. Yes, it was time. No, don't leave all at once. Yes, collapse the mines first so they won't know. These instructions were all passed without words.
It was time to pull up her roots again.
She returned home with her 'husband'. They retired to bed, she kept the charade of a loving wife going, just for one more night.
After that was done, she listened to his breathing. As always, it quickly grew slow and even. He trusted his wife, the pony he had known from foalhood crush to adult marriage. She was an earth pony like this, but with a flash, her magic returned to her. Her horn sparked, and the stallion would sleep for another eight hours. Silently she stole out of the house, and, donning the shape of some random pegasus mare who had lived in Cloudsdale decades ago, slipped unmarked into the dark streets.
In a flash, the stallion's wife was gone. Tomorrow, he would wake up alone, and he would wonder what had made her leave. What had cost him the love of his life, certainly it couldn't have been that small argument last night, the one he could barely remember. Surely their years of flirtations building to deep, enduring love couldn't end so abruptly. It was impossible for her to be gone, she must just need time alone, time for herself. She'd come back.
Chrysalis paused, with her back hoof resting on the ring of stones that marked the edge of Appleloosa's territory. She cast her eyes back to the town, which from here was little more than a few lights in the windows of the more insomniac ponies. It had been... nice. Stable. A simple life without overmuch work or stress. She could only allow herself a moment of rumination though, before turning and continuing out into the desert.
Ahead of her was another life, another few weeks of learning a mare's mannerisms and friends, before taking her place and blending in. That initial stress, those tense moments where she missed a cue or met an old friend she wasn't aware of. But it would pass, and she'd fall into place once more.
Before losing everything again.
Chrysalis sighed and spread her wings, taking flight towards Cloudsdale.