In a married life story, Kiba would develop a deeper sense of loyalty. His loyalty to Hinata would be on a whole new level compared to his loyalty to his friends or the village. He would be more protective and would do anything to keep her safe. Hinata would grow in her communication skills. Since Kiba is more outspoken, she would learn to express her feelings and thoughts more freely, which would also help her in her ninja work as she could better communicate with her teammates.
Natsu would probably become more responsible. His wild and carefree nature might be tempered a bit by his marriage to Irene. He'd still be the same fun - loving guy but would also think about Irene and their relationship. Irene, on the other hand, might soften up. She was once a very powerful and somewhat cold character, but being married to Natsu could bring out her more caring and gentle side.
In married life, Eren could develop a more domestic side. She might start cooking for Levi, which is something new for her. Levi would have to adjust to having someone so close. He would learn to share his thoughts and feelings. He might also become more protective of Eren, especially if there are threats to their relationship or their lives. Their marriage would be a journey of mutual growth and understanding.
Their relationship could develop gradually. At first, there might be some misunderstandings due to their different backgrounds. But as they spend more time together, they'd start to appreciate each other's qualities. Toneri would be drawn to Hinata's kindness and determination, while Hinata would see the good in Toneri beneath his somewhat aloof exterior.
Yes, there are some. You can try searching on fanfiction websites like FanFiction.net or Archive of Our Own. Just type in 'hinata is married to kiba' in the search bar, and you'll likely find a variety of stories with different plotlines and writing styles.
In fanfiction, their relationship could develop as they support each other's dreams. Hinata might want to improve her combat skills further, and Neji, being the skilled ninja he is, would train her. In return, Hinata could help Neji with his emotional side, as she is very empathetic. Their relationship would grow stronger as they overcome challenges together, like dealing with other clans' rivalries.
In a married fanfiction, their relationship could develop with a great deal of mutual understanding. Gaara, having grown up alone, would cherish Hinata's presence. Hinata, used to a large family, would bring warmth to Gaara's life. They would support each other in their ninja duties. For example, Gaara might accompany Hinata on missions in the Leaf village area, and Hinata would visit Suna to help with Gaara's projects there.
Their relationship could develop slowly. At first, there might be some awkwardness. Sasuke is not used to being close to someone in that way, and Hinata is very shy. But over time, they would learn to communicate better. Sasuke might open up more about his past traumas, and Hinata would be a good listener. They would support each other in their ninja duties, like when Sasuke goes on a dangerous mission, Hinata would be there to give him strength, and when Hinata is working on improving her skills, Sasuke would offer his advice.
Harry in a 'Harry Hermione Draco married life' fanfiction could develop a deeper understanding of the wizarding world's politics. Since he's married to Draco, he gets an inside look into the pure - blood families. Hermione would develop a more nuanced view of magic. With Draco's knowledge of some ancient magic, she'd expand her research. Draco would develop a sense of loyalty to his new family. He'd start to fight for the rights of all wizards, not just pure - bloods. For instance, he might join Hermione in her campaigns for equal rights for muggle - borns. Their married life would be a catalyst for their individual growth, as they constantly interact and influence each other with their different perspectives.
Aurora might develop from a rather naive princess to a more worldly and confident queen. Her marriage to Ariel would expose her to new ideas and challenges, forcing her to grow. For example, she would need to learn about ruling an underwater kingdom as well as her own land. Ariel, on the other hand, could become more patient and understanding of land - based cultures. She would have to adapt to living in a castle and dealing with court politics.
Arya would likely become more diplomatic. Since she's marrying Daenerys, she'd have to deal with more political situations. She might learn to use her skills in a different way, not just for revenge but for the good of the realm. Daenerys, on the other hand, would become more in touch with the common people through Arya. Arya's experiences growing up among the smallfolk would influence Daenerys's decisions.