I don't know that those two conditions are even remotely related. As I understand it, sex/love addictions are fixated on having someone--maybe many someones--who keeps you in a constant "love at first sight/head over heels" feeling.
Co-dependency has more to do, I think, with the overwhelming need to be needed, giving up your own life for the sake of satisfying the partner's every desire.
I'm no expert on either one, but I've never heard of comparing them or distinguishing between them.