I personally think if you were to take him back, without seeing him engaging in a program of recovery for some length of time (AA, rehab, etc.) - that would be codependent.
I personally believe that being with an alcoholic MAKES us codependent. Even if we don't live w/the person or are married to them. I engaged in rabidly codependent acts. For ex., when my ex was drunk and knocking chairs off tables on a restaurant patio, during new years a couple yrs ago, I talked the cops out of arresting him. I was therefore preventing him from experiencing the consequences of his actions. =CODEPENDENT.
If people call in sick for their As, so that they don't lose their job when they have a hangover = CODEPENDENT
Anything you do for someone , that could reasonably be done themselves WERE THEY NOT AN ALCOHOLIC=codependent
If you subvert your own needs, to try to meet the needs of someone else (and with an alcoholic, their needs can be a bottomless pit) = CODEPENDENT.
That's how I define it, anyway.