Pendejo is a strong, informal word that can mean 'idiot', 'jerk', or 'asshole', depending on the context and region. It's a common insult in many Spanish-speaking countries.
In this song, Lasso uses it to call himself out: "Quien me manda a mí, pendejo" (Who sent me, you idiot?). He's expressing self-reproach and frustration for expecting love from someone who couldn't give it, making it a raw and relatable moment in the lyrics.
This song is about holding a boundary after being hurt over and over in the same relationship. The singer names the damage plainly, even the money spent on therapy to get through it, and then explains why an apology does not undo any of that.
The chorus repeats "perdón, pero no te perdono" (sorry, but I don't forgive you) on purpose. It is less about anger and more about a line finally holding: forgiveness would mean going back to a pattern that kept costing something. The bridge circles back to the fights themselves, one partner leaving every time things got hard, to show exactly why "no" is the right answer now.