Robert Burney once coined the term "co-dependent" in the 1940s and defined it as someone who depends on another person to meet their emotional needs. Co-dependency is putting somebody else's needs before your own.

Thereby, being co-dependent is hardly the same thing as simply being dependent.  A co-dependent person may feel responsible for the happiness or well-being of others — especially if they have experienced abuse or neglect growing up. 

This term was widely used in the 1950s in the context of Alcoholics Anonymous, and Co-dependency behaviour is often found in alcoholic families.

Emotions are something you can’t see and you can’t touch them either. But one thing you can do, and that is to feel them! Some people are excellent at having their emotions buried down in the recesses of their being, protecting themselves from being hurt by other people.