Thor's arm loss in the comics can occur due to multiple reasons. Sometimes it's the result of a magical curse or a confrontation with an extremely powerful villain. The details change across different comic arcs.
Rick lost his arm when he faced a challenging situation. The circumstances were overwhelming, and despite his best efforts, he couldn't avoid the injury.
The novel I recommend to you is " Hong Kong Reborn: Entertainment Tycoon ". The novel told the story of a Chinese journalist who died on a mission and was reborn. His soul traveled to Hong Kong in 1985 and became the protagonist named Li Yangshu. In this story, Li Yangshu looked at the familiar streets and characters in Hong Kong movies and shouted excitedly," Xiangjiang, I came, I saw, I love." The main character in this novel has started to lose his arm, which might meet your needs.
The way Oliver Queen loses his arm in comics isn't always the same. Sometimes it's a result of a risky mission gone wrong, or it could be from a confrontation with a villain with unique abilities. It all depends on the particular comic storyline.
Misty Knight loses her arm in a rather tragic incident. She gets caught in a dangerous confrontation where she underestimates the enemy's power and pays a heavy price.
Perhaps the woman in the story intentionally does things to sabotage the relationship within those 10 days. It could be anything from being unfaithful to not supporting his goals and dreams.