One common theme is the exploration of their new vampire sensuality. Since they are vampires, their physical experiences are different, and this is often explored in fanfiction. Another theme could be the eternal nature of their love. Now that they are vampires, they have eternity to be together, and this is a big aspect of how their relationship is depicted. Also, the idea of their love being a powerful force that can overcome any vampire - related difficulties is quite common.
One common theme is the struggle between their two different worlds. The vampire world Edward belongs to and Bella's human world. This difference can lead to both love and hate. Another theme is the power dynamics. Edward is physically stronger and has more 'power' in some ways, which can cause friction and a love - hate relationship.
Independence is a common theme. Without being tied to Edward, Bella can be shown as a more self - reliant character. She can make her own choices, pursue her own dreams, and not be influenced by the over - protective nature of Edward.
The themes often include self - growth. After a divorce, Bella has to re - evaluate herself, and this is often explored in these fanfictions. Also, the idea of love conquering all, despite past failures. Edward and Bella's relationship is shown as something that can overcome the stigma of Bella's divorce.
Redemption can be a theme as well. Edward may be involved in bad things as part of the mafia, but through his love for Bella, he might start to question his lifestyle and try to change. Or Bella might see the good in him that others don't and help him find a path away from the more violent and illegal aspects of the mafia world.
One common theme is the struggle between two worlds. Since she is part vampire and part human (or has strong ties to both), she often has to find her place. For example, in many stories, she has to deal with the secrecy of the vampire world while still wanting to be part of normal human society.
One common theme is the exploration of their eternal love. Writers often expand on how their love endures through different challenges. Another theme is the power dynamics, especially considering Edward's vampire nature and Bella's human - turned - vampire state in some stories.
A lot of these fanfictions also deal with the idea of acceptance. Bella has to accept her new state as a vampire, and the Cullen family has to accept her as one of their own. There are often challenges and conflicts related to this acceptance process.
A common theme is protection. Edward sees himself as Bella's protector, so when he punishes her, it's often because he believes she has endangered herself.
One common theme is the exploration of their love in different situations. For example, in some fanfictions, they face new threats to their relationship, like a new vampire clan that doesn't approve of their union. Another theme is the power dynamics between them. Since Edward is a vampire with special abilities and Bella is a human (at least initially), how they navigate that power difference is often explored.
Often, there could be themes related to the breakdown of trust. If Bella cheats with Edward, it would shatter the trust that exists in their relationship. Also, themes of jealousy might be present, not just from the partner who is being cheated on, but also from other characters who might have an interest in either Bella or Edward. There could also be a theme of self - discovery, as Bella might be exploring a different side of herself through this act of cheating.