Só tem eu literally translates to "There's only me". This title phrase is a perfect example of informal Brazilian Portuguese and captures the song's entire mood.
While tem is the verb for "to have", Brazilians commonly use it to mean "there is" or "there are". In the song, it's a bold and confident declaration from the singer to his ex-lover, insisting that no one else can take his place in her heart. This common but powerful phrase is key to understanding the song's passionate message.
This song is one big, confident plea from someone who refuses to be forgotten after a breakup. Zé Felipe's character is talking directly to his ex, telling her, "Cê tá achando que vai / Não vai me esquecer não" (You think you will / You won't forget me, no). He's sure he's still in her heart and even has the receipts to prove it, pointing to the photos she hasn't deleted and the old romantic captions on social media.
The whole feeling is a mix of desperation and total self-assurance. He asks, "Se não sou eu vai ser quem / O amor teu" (If it's not me, who will be / your love?), but he doesn't wait for an answer. He provides it himself: "Só você não percebeu / Que só tem eu" (Only you haven't realized / That there's only me). It's a bold, almost cocky claim that no one else could possibly take his place, followed by a dramatic cry of "Volta, pelo amor de Deus" (Come back, for the love of God).