Some fanfics may also take a more creative approach and imagine an alternate universe where Catherine of Aragon was able to have a different relationship with Henry VIII. Maybe in this universe, political and religious factors didn't interfere as much, and they had a more harmonious marriage.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of historical fanfics, and there are likely to be many dedicated to Catherine of Aragon. The search function on AO3 allows you to easily find fanfics related to her by simply typing in her name.
Henry's desire for a male heir ended their love story. Catherine failed to produce a living son. As time passed, Henry grew tired of her and became attracted to Anne Boleyn. He then sought to annul his marriage to Catherine, which led to a long and bitter struggle with the Catholic Church.
Well, her birth into Spanish royalty was the start. Her marriage to Arthur set the stage. When she became Henry VIII's wife, that was a big event. Henry VIII's growing discontent with her due to lack of a male heir led to his push for annulment. Catherine's defense of her marriage in the face of this, and the political and religious implications of all these events are among the key events in her life story.
Catherine of Aragon was a remarkable figure. She was first married to Arthur, Prince of Wales. After his death, she married Henry VIII. She was a devout Catholic. She faced many challenges during her marriage to Henry VIII, especially as he sought to annul their marriage in his quest for a male heir. Eventually, Henry VIII broke away from the Catholic Church in part due to his issues with Catherine. She was a strong - willed woman who held her ground for a long time.
Their love story began as a political alliance. Catherine was initially married to Henry's older brother Arthur. After Arthur's death, Henry VIII married Catherine. At first, they seemed to have a loving relationship. Henry was charmed by Catherine's grace and intelligence. They had many shared interests in courtly life and the arts.
It could be a mysterious stranger she meets by chance. Maybe at a coffee shop, a guy who strikes up a conversation with her and shows an immediate interest in her life. He could be charming and different from Steve, which draws Catherine to him.
In the context of this fanfic, Catherine Rollins and Steve are likely characters created by the fanfic author. They could be original characters, or they might be based on existing characters from a particular show, movie, or book. Without more context, it's hard to say exactly who they are other than two individuals whose relationship is central to the story where Catherine makes Steve cry.
I'm not sure if there's a specific fanfic where Catherine is pregnant in 'Hawaii Five - 0'. Fanfics can vary greatly, and it would depend on the creativity of the individual fanfic writer.