Berrinches translates to "tantrums" or "fits of pique". It's a colorful and somewhat informal word that evokes a very specific image of childish or dramatic behavior.
In the song, the singer laments, "Ya no me cela ni me hace berrinches" (She no longer gets jealous or throws tantrums at me). This word is interesting because it highlights a past dynamic in the relationship, suggesting a passionate, albeit sometimes dramatic, connection that the singer now misses. It's not a word you hear in every love song, making it memorable and unique to this context.
"Cómo Te Olvido" is a heartbreak song about the strange quiet that follows a breakup. The narrator notices all the small ways their ex has moved on: no more jealous questions, no more late-night calls, no more asking mutual friends how they're doing. Even the phone number has changed.
Underneath that quiet is real pain. The narrator still reaches for a pillow that isn't there and misses a voice they can't hear anymore. The chorus asks the question the whole song circles around: "How do I forget you, if you were my life, if you're my air?" It's not really a question with an answer. It's a way of saying the love hasn't stopped just because the relationship has.
By the end, the song admits something more honest than "getting over it": even in another life, the narrator would love this person the same way, all over again.