Al garete is a popular slang phrase that literally means "adrift", like a ship lost at sea without a rudder. It's used to describe a situation that is chaotic, or a person who is living recklessly and without direction.
In the song, Mora sings "Y yo al garete llevándote de viaje" (And me, recklessly taking you on trips). He uses this phrase to paint a picture of how he was lost in the relationship, spending money and living wildly for his partner, all while she was deceiving him.
This song is a classic reggaeton heartbreak anthem about being completely played by someone you trusted. Mora kicks things off by admitting he wasn't perfect, singing, "No supe darte mi cien" (I didn't know how to give you my 100%). But the mood quickly shifts from self-blame to straight-up accusation. He realizes his ex was never honest, and he was just buying into her act. The main idea is right there in the chorus: "Siempre era yo el culpable / Y tú jugando a la inocente" (I was always the guilty one / And you were playing the innocent one).
He gets really specific about how he treated her well, buying her perfume and even weed ("Hasta te compraba pasto pa' que fumes"), while she was secretly checking his messages. The best part is when he flips the script from being sad to being angry. He says he doesn't want bad things for her, but he hopes she thinks of him every time she wakes up. The final verse is ruthless, ending with the cold line, "Recuerda que la traición, con traición se paga" (Remember that betrayal is paid with betrayal). It's a story of realizing you were the only one being honest in a relationship built on lies.