There is no overarching plot to this story, and there will likely be little to no continuity. It also doesn't really explore how they get together (and believe me, there is definitely a component of Seto being too rough around the edges and fiercely unlikeable where he leaves us in the canon, to make that transition believable). In a way, it's a little bit of a wash. But in another way, I think the most believable way to build up a relationship between Seto and someone else in a healthy, functional way, is to illustrate little moments that happen between them.

In light of the lack of plot, here's my favorite quote about endings:

In our culture, one of the more damaging things we can tell our children is the idea of 'happily ever after'—that you'll find the prince or slaughter the dragon and be happy forever—but that's not true. What happens the day after you slaughter the dragon? You still have to get out of bed. ~Raphael Bob-Waksberg