Infieles translates to "unfaithful" or "cheaters". It's a strong and provocative word that immediately hints at a complex and illicit relationship.
In the context of the song, the singer acknowledges that both he and the person he desires are being unfaithful to their current partners. He sings, "Somos infieles, envueltos en llamas" (We are unfaithful, engulfed in flames), vividly portraying a passionate, yet forbidden, connection. This word is key to understanding the song's central theme of a secret affair and the intense emotions involved.
This song is a super bold and direct message from someone who knows their ex is with someone new, but they are absolutely convinced their ex still wants them back. The singer is basically saying, "I know you're with him, but I bet you want to come back to me!"
He's not shy about it at all, inviting her to call him in the middle of the night or even stay the weekend. He's sure that her current partner doesn't love her the way he did, singing, "Yo sé que él no te quiere / Como te he querido yo" [I know he doesn't love you / Like I have loved you]. He even goes as far as to say, "Tú no le perteneces / ¿A quién quieres convencer?" [You don't belong to him / Who are you trying to convince?], believing he's left an unforgettable mark on her. It's a pretty intense declaration of lingering feelings and a strong belief that they're meant to be together, despite her current relationship.