Perhaps Catherine constantly belittles Steve in public or in front of his friends. Over time, this emotional abuse causes Steve to feel unloved and unwanted, and his heart is broken. She might make him feel like he's not good enough for her, which ultimately leads to the breakdown of their relationship.
He might become very withdrawn. He could stop going out with friends and just stay at home, feeling sorry for himself.
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.
He could also be very angry. If he feels blindsided by the break - up, he might lash out at Catherine. He could accuse her of leading him on or not being honest about her feelings all along, and this anger could be his way of dealing with the pain of the break - up.
One possible plot could be that Catherine Rollins reveals a long - held secret that Steve has been trying to keep buried. For example, she might expose a mistake he made in the past that cost his team dearly. This revelation shatters Steve's composure and makes him break down in tears as he realizes the consequences of his actions coming to light.
One reason could be that their careers are taking them in different directions. Catherine might be getting opportunities in a different location that require her to be away from Steve for long periods, and they both realize that a long - distance relationship won't work for them.
One common theme is love and relationship building. Their relationship is often explored, from the initial attraction to deeper emotional bonds.
In this fanfic, Catherine realizes that she and Steve have grown apart. She sits him down one evening and says, 'Steve, we need to talk.' With a heavy heart, she tells him that their lives are going in different directions. Steve is shocked at first but then realizes she's right. Catherine leaves, and Steve is left alone, looking at the empty space she once occupied, feeling a mix of sadness and acceptance.
One possible plot could be that her death sets off a chain of events that forces the Five - 0 team to re - examine past cases. Maybe she was involved in something that they didn't fully understand, and her death reveals hidden secrets. For example, she might have been in contact with an old enemy of the team, and that connection comes to light only after she dies.
Maybe she's kidnapped by a secret organization that believes she has some special knowledge or power. As she's held captive, she tries to outwit her captors and find a way to escape, while her loved ones are in a frantic search for her, following a trail of mysterious events that lead them closer to her location.
In this fanfic, it might be that Catherine and Steve have some underlying issues in their relationship. For example, they have different life goals or values. Catherine could meet someone who shares her newfound interests or values more closely. This could lead her down the path of cheating. The story could then show how Steve discovers the truth, and whether they try to salvage their relationship or go their separate ways.