Ship Song: 'Ruby Rider' from the show Steven Universe
Ok ok ok, this one takes some explaining! Set in a timeline where the two unfuse and the dream bubbles are no more, Nepeta has become exhausted about being used for the narrative's whims, always brushed off as an unimportant character.
She decides she wants to live her life outside of whatever new BS the other 'more important' characters churn up; to live off-grid, focusing only on being happy with beloved.
Feferi, instead, sees their new life as a chance to come back to the forefront and to become engaged hands-on with the reformation and change she wanted to see in Alternia. She would not be empress again, but she jumps at the chance to be a voice weighing in on the humanitarian sides of rebuilding troll civilization.
At odds, the two keep fighting and trying to convince the other to stay with them doing what they believe is best, but it just can't work out. Eventually, Feferi has to break it off to focus on her work, and Nepeta bitterly goes to live life by herself.
She gets exactly what she wanted; peace, adventure, fulfillment from a day's hard work. She can sustain herself and the beasts she's learned to tame for fun... but it doesn't give her any satisfaction. She misses Feferi too much.
She wants, more than anything, to get back with her... even if it means that she's once again thrown into outlandish fanfiction-like situations. At least then, she'd still be with her.
Years later, she learns about human marriage from Rose and Kanaya after they pay her an unexpected visit, and it stays on her mind. A ritual that shows a commitment to staying in redrom with one another, till their deaths? It's fantastical... and very romantic.
It's exactly the push she needed to go find Feferi again. She makes the goal to get her back, propose, and to never leave her side again.