I am still learning what co-dependency is too! So wow, I'm grateful for this thread!
Part of how I understand and experience co-dependency is allowing outside factors (mood of AH, whether AH was drinking or not, behavior of kids, how friendly or unfriendly a random person may have seemed, and other random stuff) determine my mood/feeling of well-being at any given time. The more I focus my attention inward and recognize that I do have a choice in how I allow things to affect me, the more peace I feel, and the less co-dependent I feel.
I'm sure there's a lot more to it than that, but that's my start!