Post-canon Zoyalai headcanons because I adore them—
Supermodel couple. Obviously they're not actually models, but they're both canonically attractive and they look even better together
Nikolai serves as Zoya's advisor and does a lot of the reform, schmoozing, and political scheming from behind the scenes while Zoya manages the rest of the kingdom to keep it from falling apart
After they marry, Nikolai turns the role of royal consort/royal spouse into a much more politically active one, purely because he a.) wants to help his wife, and b.) can't resist
Zoya starts to get annoyed by all the Sankta Zoya stuff, and in return for Nikolai arguing that it's a good thing she tries to spread rumors about him being a saint too
They don't have biological children because they don't want to risk passing on any part of Nikolai's merzost, but they do adopt kids. Zoya is the strict parent and Nikolai is the fun parent, but they're both very dedicated to their kids
As Nikolai starts to age, Zoya loves tracing his crow's feet and smile lines, as well as playing with the graying parts of his hair. She tries to find a way to age her body with him, even just a little bit
They bicker constantly and Zoya acts like she can't stand Nikolai, even after they've been married and parenting
They're both incredibly stubborn idiots who don't know how to take care of themselves and will gladly go until they collapse, but they will pester the other relentlessly into taking a break, going for a walk, drinking water, eating, sleeping, etc.
Zoya tries to change some of the decor in parts of the palace and is very annoyed to learn that Nikolai is occasionally a fan of an amount of luxury she finds tacky. They ultimately compromise, but it takes months of debate between two people who grew up in very different conditions
Nikolai loves to drag Zoya away from her duties to ride horses or go sailing with him, which she pretends to dislike but secretly loves
When Nikolai is much older Zoya becomes incredibly protective, purely because she doesn't want to confront the possibility of him getting closer to dying