There is oneness in two
You can't perfect for each other that's why you both are made for each other & you complete each other ...
Maybe that's why there is "ying-yang" type of things exists in this earth.
In simple language you can assume
Sun-moon, day-night, good-bad, ugly-beautiful, dark-light
See! they are incomplete without each other
one has no value without the other one and that's why it's called partners! you both do complete each other half-half