"Dos Almas" is a bolero, and Ibrahim Ferrer sings it like a man who has made peace with heartbreak but still wants you to know exactly how bad it was.
The song opens with a big claim: "Dos almas que en el mundo había unido Dios" (two souls that God had joined in the world). That was us, he says: "Eso éramos tú y yo" (that was you and me). Then it turns. "Surgió una sombra de odio que nos apartó a los dos" (a shadow of hatred appeared that pulled the two of us apart).
The ending is pure bolero drama. "Mejor fuera morir" (it would be better to die), because now they can live "ni cerca ni distante" (neither close nor far away). It is a lovely paradox: they cannot be together, and they cannot really be apart either.
Learner tip: fuera here is not "outside". It is the old-fashioned subjunctive of ser, so mejor fuera morir means "it would be better to die". You will hear this form a lot in classic boleros.