This is a duet about falling for someone you already know is bad news, and doing it anyway with your eyes wide open. Kenia Os opens by saying his cute face leaves his exes needing therapy, and she offers to pay for "las sesiones que sean necesarias" (whatever sessions it takes). That is a very funny way to start a love song.
The chorus is the whole attitude: "Arruíname la vida, que te dejo" (ruin my life, I'll let you). Everyone warns her he is a pendejo (a jerk, an idiot; it is a rude word, so careful where you use it). Her answer is a great Spanish idiom: "¿Qué le hace una raya más al tigre?" (what's one more stripe on the tiger?). It means one more scar hardly matters when you already have plenty.
Luck Ra's verse is the sweet side. He admits that with her he becomes "el más gobernado" (the most bossed-around guy), and his friends are annoyed but used to it. He would take her to Milan, cook her favourite dish, and marry her even if he lost half of everything, signing "en seguida" (right away). Notice he says vos instead of tú: that is the Argentine way of saying "you".