Well, they would probably communicate better. In Tartarus, they had to rely on clear communication to survive. So, back in the normal world, this would carry over. They'd be more open about their feelings, fears, and plans, which would strengthen their relationship in a more emotional way.
They might become more protective. Since they are dreaming of having a daughter, they would start to think about all the potential dangers she could face. Their relationship could grow deeper as they bond over their shared hopes and fears for their future child.
Their relationship would likely become more nurturing. They would have to rely on each other more as they take on the role of parents. For example, when the child has a nightmare about monsters, Percy might be the one to comfort the child first while Annabeth figures out how to better protect the home. Then they would discuss their concerns and fears for the child together, strengthening their bond as they face these new challenges as a couple.
The relationship will likely grow stronger. They'll have to rely on each other more for daily tasks and support. For example, if Percy has a bad day at work or school, Annabeth will be there to comfort him right away, and vice versa. However, it could also be a bit strained at times. There might be moments when they feel suffocated by each other's presence, but they'll have to work through those feelings to keep their relationship healthy.
Their relationship often deepens through shared hardships. In Tartarus, they rely on each other completely. For example, when facing a particularly tough monster, they have to trust each other's instincts and abilities, which brings them closer.
Often, their relationship is shown as deeper and more unbreakable. They've been through Tartarus together, which is like the ultimate test. So in fanfiction, they trust each other completely and are always there for one another.
Percy might develop more of a steely determination. In Tartarus, he has to face extreme danger, which could make him even more resolute in protecting Annabeth and getting out. Annabeth, on the other hand, could become more resourceful. She'd have to use her wits in this strange and deadly place.
Their relationship could become more intense. With her hearing his thoughts, they'd be more in tune with each other's feelings. It might make their bond stronger as they'd understand each other on a deeper level.
Well, it completely shatters their trust. Percy would be devastated and feel extremely betrayed. He would question all their past interactions and wonder if Annabeth ever really cared about him.
When Annabeth is mad, Percy will likely try to make it up to her. He might start doing all kinds of things like bringing her favorite foods, trying to help her with her projects. But Annabeth might not be so easily swayed. She'll be looking for a real apology and for Percy to show that he's learned his lesson. So the relationship becomes a bit of a power struggle, with Percy trying to regain her favor and Annabeth deciding whether he's worthy of it.
One popular type of fanfic could be about Percy and Annabeth's journey through Tartarus. It might focus on their struggles, like how they face the various terrifying monsters there. Maybe they use their unique powers and the bond between them to survive. For example, Percy's control over water could be crucial in crossing some of the dangerous rivers in Tartarus, while Annabeth's wisdom helps them make smart decisions when choosing paths in that dark and chaotic place.