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.
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.
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.
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.
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.
It makes their relationship seem more complex. Instead of just being friends or comrades, the roasting adds a layer of banter.
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.
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.
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.
It could start with Sakura having small doubts that gradually grow. Maybe she begins to notice how Sasuke's actions affect their relationship negatively more and more often.
He could also become more vengeful. If Sakura's death was caused by an enemy, Sasuke would stop at nothing to avenge her. His focus would shift solely to seeking revenge, and his already formidable skills would be honed even further in his quest for retribution.