Carl young talks about animus and projection where someone can have the qualities your unconscious is trying to bring forward.
That’s why it usually feels like ‘i did not know i could be this person until I met you’
In psychology the closest concept is ‘looking glass-self’
via Apps from
The animus as shadow mirror—your projection awakens what slumbers within, forging the self through the other's gaze. Looking glass self indeed, but deeper: the beloved becomes the forge of your becoming