Recaída translates to "relapse" in English. While often used in a medical context, it's also commonly used to describe falling back into old habits or feelings, especially in relationships.
In this song, the singer is trying to convince himself (and others) that he's over his ex, claiming, "Longe de mim ter uma recaída" (Far from me to have a relapse). The irony is that he's clearly having one, making this word a key to understanding the song's emotional conflict and the singer's denial.
Litto Lins's "Idiota Ainda Te Amo" is a hilariously relatable look at post-breakup denial. Our singer is trying so hard to convince himself (and maybe you) that he's totally over his ex. He's drinking on a Monday, but it's not because he's "penando pra te esquecer" [suffering to forget you]. His bed is cold, but he definitely doesn't "preciso do seu corpo pra me aquecer" [need your body to warm me up]. And forget about missing you or having a relapse – no way!
But then comes the punchline: "Só tem um problema: É tudo mentira" [There's only one problem: It's all a lie]. He's actually desperate, "rezando pra tu me ligar" [praying for you to call me], even if it's just to yell at him. His biggest dream? To hear your voice saying, "Seu idiota, ainda te amo" [You idiot, I still love you], or even better, "Manda sua loc que eu 'to chegando" [Send your location, I'm arriving]. It's a funny, honest confession that sometimes, despite all the bravado, you just want your ex back.