Partner.

Found an interesting quote from my favourite tv show, Modern Family.

Jay: " Why do we choose partners so different from ourselves? It's not fate or chance or cliches like "the heart wants what the heart wants". We choose our partners because they represent the unfinished business from our childhood. And we choose them because they manifest the qualities we wish we had. In doing so, in choosing such a challenging partner and working to give them what they need, we chart a course for our own growth. "