Aplaqué is the past tense of the verb aplacar, which means "to calm," "to soothe," or "to pacify." It's a very expressive word that you don't hear every day.
In the song, the singer says, "Contigo me aplaqué," meaning "With you, I settled down." This suggests he might have had a wild or restless past, but his partner's love completely calmed him and changed him for the better. It's a powerful way to describe the transformative effect of love.
This is a straight-up, no-nonsense love song from Mexican superstar Julión Alvarez. He's telling someone that his life completely changed the moment they showed up. He sings, "Que Dios tenía otros planes para mí / Y hasta que tú llegaste finalmente lo entendí" (That God had other plans for me / And until you arrived, I finally understood). It's as if he was just waiting for this person to make everything make sense.
He's completely smitten and ready to settle down, admitting, "Contigo me aplaqué, me hiciste a tu modo" (With you, I calmed down, you made me your way). He's so full of love that his heart feels like it's going to burst, and he wants everyone to know about it. He loves being seen holding hands and wants "que todo el mundo sepa que me tienes enamorado" (the whole world to know that you have me in love). It's a sweet and proud declaration of finding the one person who has it all.