Yes, it could be a dream come true for many fans. Sabrina and Harvey have a special connection in the original story. In fanfiction, their marriage could be a beautiful exploration of their relationship, perhaps showing them building a life together, facing magical and mundane challenges side by side, and growing even closer as a couple.
In this kind of fanfic, the plot could be quite complex. First, they need to figure out how they got pregnant, whether it was planned or not. Then, they face challenges like financial concerns if they are young. Their relationship might also be tested. Sabrina may have to hide her pregnancy from some in the magical world who might not approve. Harvey could be thinking about his future and how to support his family. There could also be a sub - plot about their friends helping them or some unexpected magical interference in the pregnancy that they have to deal with.
In the most common comic interpretations, Harvey and Sabrina do end up together. However, there are alternate storylines where this might not be the case. It all comes down to the creative choices of the comic writers.
After their marriage, Sabrina and Harvey could become involved in a larger magical conflict. Sabrina's powers could put them in danger, but Harvey's loyalty and love for her would keep them together. They might also make new friends in the magical world who help them in their journey. Their married life could be a blend of normal, everyday activities like going to work and having dinner together, and extraordinary magical experiences like attending a wizard's ball or helping a magical creature in need.
One interesting story could be about how Sabrina and Harvey adjust to becoming new parents. Maybe they face challenges like balancing their jobs and taking care of the baby. Another could be a magical take where the baby has some special powers inherited from Sabrina's witch side.
In some cases, it could be a powerful magical being from Sabrina's world. This being might think that the pregnancy is a bad omen or against some magical law. So, they try to stop the pregnancy or make Sabrina and Harvey's lives difficult by creating all sorts of magical obstacles for them.