Their relationship would become more serious and committed. Before the pregnancy, they might have just been exploring their feelings, but now they have a future together to think about. They would rely on each other more, with Peter being more protective of Sue and Sue depending on Peter for emotional support during her pregnancy.
In the fanfiction, the relationship would change drastically. The pregnancy would force them to communicate more openly. They would have to discuss things like where they will live, how they will raise the child, and what to do about their superhero identities. Peter would likely become more domestic - minded, spending less time on his Spider - Man duties and more time with Sue. Sue would also change, becoming more vulnerable and relying on Peter's strength in a different way than she did before.
The relationship between Peter and Sue would evolve into a much deeper bond. With Sue being pregnant, they would be sharing a very intimate experience. Peter would have to step up and be there for Sue in ways he hadn't before. He might start to see her as not just a fellow superhero but also as the mother of his child. Sue would start to view Peter as a long - term partner, someone she can build a family with. There would be more trust between them, and they would be more united against any external threats that could harm their family - in - the - making.