Pasional translates to "passionate" and is a less common, more intense way to describe strong emotions than the everyday apasionado.
In this song, Ricky Martin's "Corazón no seas pasional" (Heart, don't be passionate) is a plea to his own heart to resist the overwhelming, fiery love he feels for a woman who is causing him pain. It highlights the internal struggle between reason and intense emotion, making it a compelling word choice.
Ricky Martin spends this whole song arguing with his own heart like it's a separate person who won't listen to reason. He opens with the plea that gives the song its title, "Corazón no vuelvas más con ella" ["Heart, don't go back to her anymore"], and from there it plays less like a love song than an intervention he's staging for himself.
The physical detail is what sells it. "Si la abrazo tiemblo como un papel" ["If I hug her, I tremble like a paper"] is such a specific, almost embarrassing image that you believe he's actually lived it. He knows exactly what's wrong with the relationship too: "Ella es fuego lento besándome" ["She's a slow fire, kissing me"], someone who burns him gradually instead of all at once. By the chorus he's begging his heart to just say goodbye, "Corazón dile adiós" ["Heart, say goodbye"], because he can't quite make himself do it.
Ricky Martin was turned down by Menudo twice for being too short. The third audition worked, and in 1984 Enrique Martín Morales joined the Puerto Rican boy band at twelve, staying past his age-mandated retirement until July 1989. Two solo ballad albums followed, Ricky Martin (1991) and Me Amarás (1993), before he changed direction.
A Medio Vivir (1995) carried "María", his first hit well beyond Latin America, and Vuelve (1998) carried "La Copa de la Vida", the official song of that year's World Cup in France. He sang it at the 1999 Grammy Awards, where Vuelve took Best Latin Pop Performance, and that spring "Livin' la Vida Loca" spent five weeks at number one on the Billboard Hot 100 as the lead single from his first English-language album. He has gone on recording in Spanish throughout: Almas del Silencio (2003), and A Quien Quiera Escuchar (2015), which won Best Latin Pop Album. He came out publicly in 2010, and his foundation campaigns against human trafficking.