Puntos suspensivos literally translates to "ellipsis," the punctuation mark consisting of three dots (...). It's a wonderfully creative and uncommon phrase to find in a song, making it a great one to learn!
In this track, Piso 21 uses it as a metaphor for a relationship left hanging and unresolved. Just as an ellipsis in writing suggests there's more to come, their romance has been paused without a clear ending, leaving the singer in a state of uncertainty and longing.
This song is one big, dramatic plea to an ex who left things unresolved. The singer feels like their relationship has been left on "puntos suspensivos" (an ellipsis...), and he is absolutely not okay with it. He's so desperate for an answer that he says, "Responde ya, que esto es de vida o muerte" (Answer now, this is a matter of life or death). It's a bit over the top, but it shows how intensely he feels.
He completely rejects the idea of being just friends, singing, "No me lo pidas, no seré tu amigo" (Don't ask me, I won't be your friend). Instead, he insists, "Estar contigo es mi destino" (Being with you is my destiny). He's stuck in a loop of wondering if he wasn't good enough and feeling like he's losing his dignity, but he still feels like he belongs to her. He's refusing to accept the ambiguous ending and wants a real conclusion, one way or another.