Aferrado comes from the verb aferrar, meaning "to grasp" or "to cling to". It's a vivid word used to describe someone who is stubbornly holding onto a person, idea, or feeling, even when it might be better to let go.
In the song, the singer would rather suffer for a few months than "vivir aferrado a tu amor toda la vida" (live clinging to your love his whole life). It perfectly captures that feeling of being emotionally stuck, unable to move on from a past love.
This song is the ultimate anthem for a breakup where you know your worth. The singer isn't begging his partner to stay; he's holding the door open for them. He accepts the relationship is over, saying he'd rather "sufrir un par de meses tu partida" [suffer your departure for a couple of months] than "vivir aferrado a tu amor toda la vida" [live clinging to your love my whole life]. It's a powerful way of choosing short-term pain over long-term misery.
He makes it very clear this is a final decision, telling them, "Si me alejo de tu vida es para siempre" [If I walk away from your life, it's forever]. But the real sting comes at the end. After admitting that it hurts to lose them, he delivers the final blow: he swears that "un amor como el mío... No te llegará dos veces" [a love like mine... won't come to you twice]. It's a confident, heartbreaking, and slightly bitter goodbye that says, 'You're losing more than I am.'