Codependency = worship of another person, where primary identity is gained from being in a role to serve that person. Therefore, objective judgment is lost and it is impossible to hold each other accountable to be "rightly joined together" , because that person is in the role of God to you.
Interdependency = healthy relationship where need is still present, like in the Body, where the leg needs the foot, but identity comes primarily from the head, which is Christ, not in being a foot for the leg.
The foot is a daughter or son of God first, not "of use" to the leg first.
That means, when the foot is hurting the leg, or the leg is hurting the foot. They both have the power to speak up, because both sets of needs are important to Jesus, the head, and they are both getting their identity from him, not from walking on eggshells around the other one.