Some fanfictions might focus on the cultural differences between them. Peter is from a more normal human upbringing in terms of family and society, while Laura has a very different experience. Their marriage could be a journey of understanding and accepting each other's cultures. For example, how they celebrate holidays or deal with family traditions. This can create a lot of interesting character interactions and story development.
Fanfiction.net could also be a good place to look. However, the quality and content can vary greatly. Some stories might be more focused on their relationship leading up to marriage, while others might explore their married life. You'll need to sift through the search results to find what you're interested in.
A possible plot is that an old enemy of Peter discovers his relationship with Mystic and tries to use her to get to him. This could lead to a race against time for Peter to save her. Also, their marriage could be a source of strength for both of them. Mystic could use her powers to create illusions to help Peter in his crime - fighting, and in return, Peter protects her from the dark forces that are interested in her powers. They could also go on adventures together, exploring different dimensions where Mystic's powers are enhanced or different versions of Peter exist.
One idea could be a crossover with the X - Men. Laura Kinney, being a part of the X - Men universe, could interact with other mutants in new and exciting ways. For example, she could team up with Storm to take on a powerful enemy that threatens both mutants and humans. Another idea is a crossover with the Marvel Cinematic Universe. Imagine Laura in a world with the Avengers, and how she would handle the different dynamics and challenges there.
One plot idea could be Peter and Live Wire facing a new supervillain together as a married couple. They'd have to combine their powers and their relationship skills to defeat the foe. Another could be them trying to keep their identities secret from the public while also dealing with the normal married life things like bills and family visits.
One possible plot idea could be that Peter Parker meets a superfan who he ends up marrying in an unexpected turn of events. Maybe they initially bond over his superhero adventures and as they get to know each other better, love blossoms. Their relationship could then face challenges like keeping his identity a secret from the public while being in a high - profile relationship.
Maybe Peter discovers Marinette's Ladybug identity when he's in Paris on a mission. He initially mistakes her for a threat but then realizes she's a hero too. They start training together and sharing their experiences of being young superheroes. Marinette helps Peter with his stealth skills, which are useful for his Spider - Man activities, and Peter shows Marinette some new ways to use her yoyo in combat. This could lead to a romantic relationship as they grow closer through their shared superheroics.
One plot idea could be them facing a new supervillain together while also dealing with the typical married issues like who does the dishes or takes out the trash. Another could be that they're trying to keep their relationship a secret from the public eye because of all the attention it would draw.
One plot idea could be them dealing with the cultural differences between their two worlds. Peter's from the superhero world and Sam from her own fictional setting. They might struggle to understand each other's values at first but then grow closer.
One plot idea could be that they meet during a multiverse - related event. Maybe the fabric of reality is torn, and they end up in each other's universes. They have to work together to fix the problem while also dealing with their growing feelings for each other.
If we consider Peter Parker and Supergirl. Supergirl is a powerful being from Krypton. Their marriage could involve Peter having to deal with her super - strength and also the fact that she has a different set of values coming from an alien culture. They could work together to protect both Metropolis and New York, combining their powers and intelligence.