Actually, when the two of them first started out, it wasn't like this. Akemi came to keep an eye on Xiaotian, but her goal wasn't to stay in the organization—it was to escape it.
So, as time reveals a person's true character, Akemi realized that Xiaotian was just like her: neither of them wanted to be controlled by the organization. That was when she finally opened up to him.
Consequently, in the year they turned eighteen, the two of them officially became husband and wife.
Chapter 591