Ex-aequo is a Latin phrase meaning "from the equal" and is used in French to describe a tie or when two things are on equal footing. It's a more formal and less common word than simply saying
Have you ever wanted someone all to yourself, but worried that made you seem selfish? In "Égoïste," French singer Vitaa explores this very feeling. She sings from the perspective of a woman in a complicated relationship with a man who has just gotten a divorce. He's promised her a fresh start, saying, "for you, I'll start over from zero," but his heart seems to still be in the past.
This leaves the singer feeling insecure and frustrated. She asks, "How can I become your family without replacing your family?" and wonders if she's arrived at the right time. She feels like she's being painted as the "bad guy" for wanting his full commitment, while he hesitates to choose her. The song captures the emotional turmoil of wanting someone's whole heart when they're still caught between their past and their future.