In most Spider - Man novels, Mary Jane is indeed present. She's not just a love interest but also a strong character in her own right. For example, in some novels, she has to deal with the knowledge of Peter's double life as Spider - Man. This creates interesting story arcs as she struggles with the danger that comes with loving a superhero, and also has her own life and goals that she is trying to achieve. Her presence in the novels helps to humanize Peter Parker and makes the story more than just about a superhero's adventures.
In some Spider - Man fanfictions, Mary Jane being pregnant can add a whole new layer of drama. It could mean that Spider - Man has to balance his superhero duties with being a soon - to - be father. Maybe he'll worry about protecting his family more than ever, and there could be new villains who target his unborn child or Mary Jane to get to him.
In a fanfic like this, MJ might get her powers in a freak accident. Peter, being Spider - Man, is hesitant at first about MJ joining him in the superhero world. But MJ is determined. She creates her own Spider - Woman costume and starts patrolling the city on her own. Eventually, Peter realizes he can't stop her and they start working as a duo, with their relationship evolving into a more equal partnership.
Spider-Man doesn't kill Mary Jane in the comics. Their storylines are filled with ups and downs, but not that kind of tragic event. Mary Jane is often a supporting and important figure in his life, not a victim of his actions.
In most Spider-Man comic runs, Mary Jane survives. However, there might be alternate universes or special story arcs where her fate varies, but in the main continuity, she lives on.
In some storylines, Mary Jane wasn't killed. But in specific alternate universes or non-canonical tales, her death might have occurred due to various villainous attacks or tragic circumstances.
One possible plot could be that MJ discovers she has powers and becomes Spider - Woman. Peter is both proud and a bit worried as he wants to protect her. They could team up to fight a new villain in New York. MJ might struggle with keeping her identity a secret from her friends and family, just like Peter did when he first became Spider - Man.
She could be developed by showing her more independent side. For example, she starts her own small business or gets involved in a community project. This would show that she has her own goals apart from her relationship with Peter.