Descuidé comes from the verb descuidar, meaning "to neglect" or "to not pay attention to". It's the emotional core of this heartbreaking song of regret.
In the lyrics, the singer confesses, "Tontamente descuidé... de tu amor" (Foolishly I neglected... your love). He uses this single word to express how he took his partner for granted, stopped being thoughtful, and ultimately lost her. It's a powerful admission of fault that sets the tone for the entire song.
We have all seen someone ruin a good thing by getting entirely too comfortable, and that is the exact regret powering this live track from Grupo Firme. The singer starts by admitting his partner gave him everything without demanding a thing back: “Tú me entregabas todo sin pedirme nada” [You gave me everything without asking for anything]. Life was great, but then ego and laziness took over. He sings, “Hasta que un día me confié / Y tontamente descuidé” [Until one day I grew overconfident / And foolishly neglected you]. In Spanish, saying you became “detallista” means you pay attention to the little romantic gestures. Here, he admits he stopped doing that completely: “Dejé de ser el detallista aquel / Y ya jamás te mandé flores” [I stopped being that thoughtful guy / And I never sent you flowers again]. No flowers, no effort, just pure complacency.
He does not sugarcoat his behavior at all. In fact, he calls himself out with some harsh language: “Fui un animal que te ofendía” [I was an animal who offended you]. Calling yourself an animal in everyday Spanish is a blunt way to say you acted reckless, rude, or completely lacked basic human manners. By the time he realized he pushed her past her breaking point—“Hasta que un día te cansé” [Until one day I tired you out]—her feelings were totally gone. Now he is left singing “Y ahora por ti me estoy muriendo” [And now over you, I am dying], serving as a loud, honest warning about what happens when you take someone's love for granted.