I will try my best to answer.
One common theme could be isolation. When Percy has a mental breakdown, he might isolate himself from his friends and loved ones. Another theme could be self - discovery. Through the breakdown, he may start to understand himself better, his fears and insecurities.
It's possible that the husband's plan is to expose his wife's cheating in a very public way. He could tell all their friends and family about what she's been doing. However, this is a rather vindictive approach and might not be the best solution in the long run. Another aspect of his plan could be to change the financial situation so that she doesn't have an easy time if she decides to leave him for the other person. He might start saving more money in his own accounts or selling off some joint assets carefully.
I'm not sure of specific 'percy has a mental breakdown fanfiction' off - hand. But you can try searching on fanfiction platforms like Archive of Our Own. They usually have a wide variety of fan - made stories and you can use the search terms to find relevant ones.
One possible reaction could be that the husband chooses to communicate openly with his wife about why she cheated. He might try to understand the underlying issues in their relationship that led to this. For example, if there were problems like lack of communication or emotional disconnection, he could focus on fixing those.
The story could end with the husband realizing that he doesn't want to be with a person who cheats on him, regardless of his plan. So he might quietly and amicably end the relationship, dividing their assets fairly. Or, if the wife realizes that she made a huge mistake and the husband's plan made her see the value in their relationship again, they could end up with a stronger bond. But this would require a lot of work from both sides, like being completely honest with each other about their feelings and expectations.
One consequence is the breakdown of trust. The husband may find it very hard to trust his wife again, which can severely damage their relationship. Another is emotional turmoil for both parties.
It's a strange and unusual plot. Maybe the wife is drawn to the ghost woman's mysterious allure or is under some sort of supernatural influence.
It could be a wild and spooky tale. Maybe the ghost seduces the wife or possesses her to make her do it.
One story could be that the husband found out his wife was cheating. Instead of getting violent, he quietly gathered evidence. Then he exposed her affair to their families and friends, which led to her being ostracized in their social circle.
Well, perhaps the wife's friend and the husband could become good friends. They might start sharing common interests like a love for books or a particular sport. For example, if the husband is into fishing, the wife's friend could also be interested and they end up discussing fishing techniques and planning fishing trips together, which could strengthen their friendship in a platonic way.