Healthy relationships are a result of people being together because they want to be, not because they have to be. They don't have to be with each other, instead they want to be with each other. Each of them has enough emotional independence (they're not needy), so they can give to the relationship; they are in a position to give and not just take. When each person has enough independence (emotionally) then they are in a position to receive from the other person and also replenish their partner by giving emotionally. So, interdependence is only possible after each person has sufficient independence.
Just like the U.S. had to become independent of Great Britain before the U.S. and Great Britain could work together as allies. So, this Independence Day, are you and your partner working together as interdependent allies?