Antojos literally translates to "cravings," like a sudden urge for a specific food. However, it can also mean "whims" or passing fancies.
In the song, Shakira uses it with a sharp, emotional edge, singing, "Me tratas como una más de tus antojos" (You treat me like just another one of your whims). She's accusing her ex-partner of treating her not as a person to be loved, but as a fleeting desire to be satisfied and then discarded. It's a powerful word that perfectly captures the feeling of being used.
Ever been so mad at someone for lying that all you can do is sarcastically congratulate them on their performance? That's exactly what Shakira is doing in this song. She's realized her partner was completely fake, saying, "Me di cuenta que lo tuyo es falso" [I realized that you are fake]. She's completely done with the lies and fake apologies, telling him, "Te conozco bien y sé que mientes" [I know you well and I know you're lying]. The whole song is built around this incredibly sharp, sarcastic compliment: "Te felicito, qué bien actúas" [I congratulate you, you act so well]. She even says he deserves an Oscar for his great acting!
Rauw Alejandro jumps in with his side of the story, but he's not exactly apologizing. He sounds a little bitter, reminding her of their past and even getting a bit petty. He says he won't block her on social media specifically so she can see his new life: "No te bloqueé de las redes para que veas la otra en la Mercedes" [I didn't block you from social media so you can see the other girl in the Mercedes]. But Shakira has the last word. She's seen the truth, telling him his actions didn't break her skin, but they did open her eyes: "Tu herida no me abrió la piel, pero sí los ojos" [Your wound didn't open my skin, but it did open my eyes].