The most heart-wrenching part about the CEO's substitute ex-wife was probably the various entanglements and contradictions between the protagonist and the CEO in the novel, as well as how the protagonist finally realized his wrong love and realized that the person he loved deeply had left him. In this process, the protagonist may experience many setbacks and pain, including regret for the past and disappointment for his current lover, but in the end, he will understand his heart and find his own happiness again.