This fanfic can make the relationship look more realistic. In real life, relationships often have problems. By having Sakura regret choosing Sasuke, it shows that even in a fictional world based on Naruto, relationships can be full of doubts and second - thoughts. It might also change the perception of Sasuke as not being the ideal partner for Sakura, as his actions and attitude might be shown in a less favorable light in the fanfic.
In the fanfic, it could be that Sasuke doesn't appreciate Sakura enough. She might pour out her love and support for him, but he doesn't return it in the way she hoped. Sakura may have expected a more reciprocal relationship where her feelings are acknowledged and valued. Since that's not the case, she starts to regret her choice of Sasuke.
It shatters the idealized view of their relationship. In the original story, they are seen as a somewhat unlikely but ultimately happy couple. But in this fanfic, it shows that there were underlying issues that could lead to regret.
The relationship would become very tense. Naruto would likely avoid Sakura and Sasuke. There would be no more of the friendly banter or the complex emotional triangle that was there before. It's a complete shift from their normal relationships in the original story.
Maybe in the fanfic, Sasuke has some personality traits that become more difficult for Sakura to handle over time. For example, his brooding nature might start to feel like emotional unavailability rather than just his usual self. This could lead to her regret.
The relationship often becomes more strained. Sasuke's punishment can make Sakura feel resentful at first. But over time, it can also lead to her becoming more independent as she tries to prove herself to him.
In these fanfics, one characteristic is the growth of their relationship. At first, Sasuke may be aloof, but gradually he opens up to Sakura. Sakura, on the other hand, is always steadfast in her love. Another is the mutual support. They often face difficulties together, be it in battles or in rebuilding their world, and they rely on each other's strength. Also, there's the element of deep understanding. They come to understand each other's past traumas and insecurities, which brings them closer.
Their relationship could become stronger. With a son, they have a new bond that ties them together even more. They might communicate more often and share their parenting experiences. They could also rely on each other more in terms of protecting their family.
The relationship can start with a moment of vulnerability. For example, if Sakura is in a dangerous situation and Sasuke comes to her rescue. His licking of her (in a non - sexual, affectionate way like licking a wound) can be the first sign of his deeper care for her. This could lead to Sakura realizing that Sasuke's feelings for her have changed, and she starts to open up more to him.
The relationship might become more equal. Since Sakura is stronger, Sasuke can't look down on her as he might have in the original story. They could become more like true partners, respecting each other's abilities.
Often, it starts with Sakura having internal doubts and slowly realizing that things aren't as she hoped in her marriage. For example, she might notice that Sasuke doesn't communicate well with her.