One of the principles that is crystal clear in the bible is that God wants us to trust Him and Him alone. A person who is co-dependent is seeking to find their identity in another person. In some cases the person is so dependent on another person that they don’t realized they are being manipulated or controlled...or they are doing the manipulating and controlling. God wants us to trust in Him completely and when we look to another person to find our identity we are in direct violation of His commandments.

Psalm 118:8 It is better to trust in the Lord than to put confidence in man.