Olvidémonos is the reciprocal command form of the verb olvidar (to forget), meaning "let's forget each other."
It's a poignant and central word in the song, encapsulating the theme of a mutual, albeit painful, decision to move on from a past love. The use of the reciprocal form highlights the shared experience of letting go, making it a powerful and emotionally resonant choice for the lyrics.
This song is all about two people deciding to really end a relationship, even though they loved each other a lot. The singer tells the other person, “Olvídate de mí” [Forget about me], and promises “Que yo también me olvidaré” [I’ll also forget]. It’s not a casual breakup. They are saying they both have to erase each other from their lives on purpose, almost like an agreement to cut all emotional ties.
What keeps it from being cold is that he also admits he will still keep something inside: “Guardaré en mi corazón las caricias y los besos que nos dimos” [I will keep in my heart the caresses and the kisses we gave each other]. So he wants them to forget each other in daily life, but he knows those memories will stay with him. The strongest line for me is “Yo te juro que no vuelvo aunque tenga que llorar” [I swear I won’t come back, even if I have to cry]. It sounds like he’s talking to himself as much as to the other person, forcing himself to be strong. When he repeats “Olvídame” [Forget me] again and again at the end, it feels like slamming the door shut so neither of them can run back, no matter how tempting it is.