One possible plot could be Deku finding out his partner cheating through overhearing a conversation. He might be heartbroken and initially go into denial.
Perhaps Deku discovers evidence of the cheating like text messages on his partner's phone. This could lead to him confronting his partner and a big emotional showdown. He might then isolate himself for a while, feeling betrayed and losing confidence in himself and relationships in general.
In some versions of this fanfiction, Deku's friends could find out about the cheating before he does. They then have to figure out how to break the news to him. This could lead to some internal conflict among his friends about whether to tell him or try to handle the situation themselves. It also shows how Deku's relationships with his friends are affected by this betrayal in his romantic relationship.
One possible plot could be that Issei discovers his partner cheating through finding love letters or messages from the other person. He then goes through a phase of heartbreak and self - doubt, questioning what he did wrong.
He might cry a lot. Deku is very emotional, and being cheated on would be a very painful experience for him. He could also get angry, which is rare for him, but this situation would be so unjust that he might not be able to hold it in. He'd probably start to question his self - worth too, thinking that there was something wrong with him that made his partner cheat.
One possible plot could be that Deku is mind - controlled to fight against his friends. His friends then have to figure out a way to break the mind control without hurting him. Another plot might involve the villain using Deku's mind - controlled state to gain access to secret hero information.
Well, in this type of fanfiction, perhaps the plot unfolds with Naruto coming home early one day and catching his girlfriend in the act with another person. This discovery could send him into a downward spiral of self - doubt and anger. He might then go on a journey to rediscover himself and his worth, distancing himself from his old life and relationships. Or, it could be that the girlfriend tries to deny the cheating at first, causing more drama and confusion in Naruto's life.
One possible plot could be that Naruto discovers his partner has been cheating with someone from another village. This could lead to a lot of inner turmoil for Naruto, as he might question his own self - worth and his ability to judge people. He could become more withdrawn and focus solely on his ninja training to numb the pain.
Well, it could also be Harry who is wrongly thought to be cheating on his partner. In the fanfiction, perhaps some false rumors are spread by his enemies. They create a situation where his friends start to doubt him, and his relationship is put under great strain.
One possible plotline could be Naruto's initial shock and disbelief. He might go through a period of self - doubt, wondering what he did wrong. Another could be his journey to find himself again after such a betrayal. He might focus on his ninja training more intensely to distract himself from the pain.
One possible plot could be that Kuroko's quiet and unassuming nature makes him an easy target for a group of jealous basketball players. They might try to undermine his confidence before a big game by stealing his training equipment or spreading false rumors about him.
Another plot could involve Tails trying to hide his sickness at first because he doesn't want to worry his friends. But as it gets worse, he can't hide it anymore. His friends then feel guilty for not noticing earlier and they all come together to take care of him and find a remedy.
Well, perhaps in this fanfiction, there could be a plot where a dark curse is placed on Hinata. As the curse takes effect, she gradually weakens until she finally succumbs and is killed. It could also be that a misunderstanding leads to her being in the wrong place at the wrong time and getting killed accidentally.