I'll Gladly End This Engagement: Best Wishes to the Lady Who Stole Him

Felicia, the daughter of a marquess, is happily engaged to Silas, the son of a marquess, and they are living happily ever after.
She is spending her days happily.
The only problem is that her cousin Maisie follows them on their dates.
She is paranoid about everything and does not listen to her cousin's warnings,
Silas only accepts her and grows frustrated with her.
Maisie also has a nasty habit of stealing.
Before she knows it, she and Silas have become closer than her fiancé....
Felicia's feelings cool down at once and she decides to step aside with a salty attitude.
At that time, the second prince, Kevin, hears a rumor and begins to approach her fiercely....?