"Until Yesterday" by JC Chasez is a song about discovering betrayal and deception in a romantic relationship. The lyrics tell the story of the narrator finding a letter on their dresser, revealing that their partner is expecting a baby with someone else. This discovery makes the narrator suspicious of their partner's actions and leads them to confront their partner, who becomes angry and defensive. As time passes, it is revealed that the baby is not the narrator's blood type, indicating that their partner had been unfaithful. The narrator expresses their love for their partner and the hurt caused by the lies and betrayal. They question why their partner kept them while engaging in a sexual relationship with someone else and wonder if it was just a one-time affair or something more significant. The chorus of the song emphasizes that playing with fire leads to negative consequences and urges the partner to learn from their mistakes. The narrator acknowledges their love for their partner but also recognizes the need to move on from the situation. They highlight the sadness and loneliness caused by the deception and stress that there is nothing left to say. Overall, "Until Yesterday" is a song that explores the emotions of heartbreak, betrayal, and the realization that sometimes love is not enough to mend a broken relationship. It serves as a reminder to be cautious in relationships and to trust in oneself when faced with deceit.
