A co-dependent relationship occurs when one person needs the other who in turn needs to be needed like I said before co-dependency it's not just reserved for romantic relationships as we may assume it can really take place in any relationship which becomes unbalanced. The term first appeared amongst researchers who were studying people with addiction and they used it to describe the almost lopsided or you know one-sided enabling relationships between someone who was struggling perhaps with alcohol abuse or substance abuse. It kind of moved its way into a acoholics anonymous meetings and then it became a common term through that as it became more accessible to people, now it's been embraced pop culture and pop culture.