Perhaps their relationship becomes more of a friendship based on mutual understanding. Percy has had his own share of being in difficult situations, and Calypso has been alone for a long time. When they meet again, they might share their feelings and experiences, which deepens their connection and makes their relationship more than just a memory of their past encounter.
Well, it often becomes strained. Annabeth might feel hurt and confused, which could lead to her becoming more reserved or even angry towards Percy. For example, she may start to question their friendship or relationship.
Luffy might be more confident and less like a little kid around Shanks. He has grown a lot, and Shanks would notice this. Their relationship could become more of an equal partnership in terms of respect.
Their relationship could develop through shared experiences. For example, they might go on a quest together to find a lost relic. During this quest, they learn more about each other's strengths and weaknesses and grow closer.
It could become more complex. As adults, they have different responsibilities and experiences. Their relationship might start off a bit strained as they try to fit into each other's new lives. But eventually, they could find a new level of understanding and respect for each other.
Their relationship could become stronger. If they meet in a difficult situation, they would rely on each other like they used to. This shared experience might make them realize how much they still need one another in their lives, thus deepening their bond.
Maybe they will have a friendly conversation, reminiscing about the past. Percy could share his new adventures, and Calypso might tell him how she has been since they last met.
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.
At first, it might become strained. Annabeth could be hurt and pull away from Percy. She might not want to be around him as much.
When they meet again, the relationship could start off a bit rocky as Wendy has grown and Peter is still the same. But as they spend more time together, they start to understand each other better. Wendy might teach Peter some things about growing up in a way, and Peter could show Wendy the magic of Neverland all over again. Eventually, they could become closer friends or even something more, depending on the direction the fanfiction takes.
At first, Calypso might be in awe of Percy's new godly form. But soon, they realize that they are equals in many ways. Their relationship develops as they face opposition from some of the other gods. They support each other through difficult times, like when some try to undermine their marriage. Percy, with his courage, and Calypso, with her wisdom, make their relationship strong and they become a power couple in the divine realm.