Estribos literally translates to "stirrups," like those used when riding a horse. It's an unexpected word in a romantic song, making it quite memorable.
However, in the context of this song, the phrase "perderemos los estribos" is an idiom meaning "we will lose control" or "we will lose our heads." The lyrics suggest that if the former lovers see each other again, they won't be able to resist their passion, creating a vivid image of losing all self-control.
Have you ever known that seeing an ex is a bad idea, but you still want to? That's the feeling at the heart of this passionate song. The singer has unexpectedly reconnected with a former lover after a difficult breakup. He admits their love was real and powerful, so much so that it "doesn't have an expiration date" ("no tiene fecha de caducidad").
Because their connection is so intense, he warns that they shouldn't see each other. He knows if they do, they'll "lose control" ("perderemos los estribos") and end up alone in a room "with the lights off and our bodies on fire" ("con las luces apagadas y los cuerpos encendidos"). It's a powerful struggle between knowing what's right and giving in to temptation. In the end, he leaves the choice up to his ex, asking: Should they risk it all for one more passionate night?