Atrofien comes from the verb atrofiar, meaning to atrophy or waste away. It's a strong, somewhat medical term not commonly found in song lyrics, making it quite unique and memorable.
In the context of the song, the singer says, "tengo que dejar que te atrofien" (I have to let them atrophy you). This suggests a painful decision to let go, allowing something or someone to diminish or fade away, rather than holding on and causing more harm. It conveys a sense of sacrifice and the difficult choice to allow a relationship or feeling to wither for a greater good.
Graciela Beltrán's "Deseo" is a really intense song about a love that has to end, even though the singer is still deeply in love. She knows she loves him, but she has to tell him the opposite, saying "no me conviene alimentar el futuro" [it's not good for me to feed the future]. It's a heartbreaking situation where she feels she needs to let him go, even if it means letting him be "atrofien" [atrophied] or damaged by the experience.
What's truly striking is her wish for him after they part. Instead of wishing him well, she says, "te miento y que jamás vuelva a ser tan feliz que nunca encuentres momentos que me hagan feliz" [I lie to you and may you never be happy again, may you never find moments that make you happy]. She wants his whole world to turn gray with regret, wishing "que el arrepentimiento ya te vuelva un tormento" [may regret become a torment for you]. It's a powerful and almost shocking expression of pain and a desire for him to feel the weight of their separation, making it a truly unforgettable listen.