Aconseja comes from the verb aconsejar, meaning "to advise" or "to counsel". It's a slightly more formal and less common word than simply saying "tell me" or "say to me", making it stand out.
In the song, the artist sings, "Todo el mundo me aconseja que me ponga a mí de primero" (Everyone advises me to put myself first). This word highlights the internal conflict of the singer, who is receiving advice but struggling to follow it due to his deep feelings for someone else.
"Para Amarte a Ti" is about loving someone so much that you decide to walk away from them.
The narrator keeps falling back into old, painful patterns, and admits he's the reason he broke his partner's heart before. Rather than keep hurting her, he tells her that loving her the right way means giving up the fight with himself first, even if that means letting her go.
It's a song about self-awareness in a relationship: knowing your own flaws well enough to protect someone else from them, even when it costs you the person you love.