OllieTheDead

Vi doesn't have any obligation to be with Caitlyn or care about her. She could have, very easily, run away with Jinx after "breaking" her out of jail and never looked back - in fact, Caitlyn herself is surprised when that's not what happens. Even after Jinx locks her in and then Caitlyn opens the cell, Vi could have run after Jinx then. In canon, after the battle, Vi had no reason forcing her to return to Caitlyn. She could have joined up with Ekko and the Firelights, she could have lived on her own, hell, she could have even left the entirety of Piltover and Zaun behind.

But no, she chooses to stay with Caitlyn. Because that's the woman she fell in love with, and being with Caitlyn brings her happiness. Simple as that. She's not family, she's not a childhood friend/little sibling figure connected to her past (like Ekko), she's this girl that Vi willingly let in and is willingly choosing to make an important part of her life.

As somebody who also has been saddled with the expectation of being the caretaker of many people in my family, who's had to learn to balance those responsibilities with the things I want to do and other types of relationships I want to have, it just makes me really fucking happy to see a character go through an arc that involves them learning to value themselves and their own happiness over always having to prioritize others because of familial ties.