I have been in the same situation as you and went to Al-Anon for many years and received counseling for the same thing. Here is what I have discovered for me (I don’t know if it applies to you): co-dependency is a survival mechanism we develop to deal with the unbearable situation we find ourselves in. We become what others expect us to be, and really don’t develop a sense of “self”. They call this behavior “chameleon behavior” because like a chameleon, we tend to take on the “colors” of those we deal with. We desperately want to be loved and accepted, so we develop behavior aimed at pleasing the people around us. We also fail to see the reality of the situation we are in and make excuses and enable the behavior of the alcoholic–that is the denial. Co-dependency is VERY self-centered, even though we think we are just making others happy, because everything is aimed at easing our pain. We relate to the world (unconsciously) as if everything depended on us, and become very inward focused, although outwardly we may not appear that way. We end up taking care of everybody but ourselves, because we have such a negative self-image. We may think of ourselves as being humble, but actually it is a form of pride, because we refuse to see things as they are and do not want to seek help. Everybody else needs help, but we don’t. As I said, it is a very self-centered way to live, because the ultimate goal is to ease the pain and guilt in ourselves, not really to benefit others.
The way to overcome this, from a Catholic standpoint, is actually found in the first 3 steps of the 12 steps–to admit that you are powerless to control things, to find God, and to turn your entire life and will over to God. Followed by searching yourself thoroughly and honestly and confessing your faults and weaknesses to another person. (4th & 5th steps). For Catholics, we can do this in the Sacrament of Confession. Often Catholics in Al-anon will seek out a priest to do the 5th step. This is a daily, ongoing process, to attempt to live in God’s will and constantly seek it. This actually what the Church teaches us to do, this is what the Saints strived to do so perfectly. This is how to die to yourself. Plus the other things–asking God to remove your faults, making amends and restitution to those you have hurt, prayer, meditation, etc. All of these have the effect of helping us die to ourselves and putting on the Mind of Christ. This will help us to develop the theological virtues of Faith, Hope, and Charity and bring us out of our self-centeredness. In my life, a miracle was worked. I have by no means achieved my goal, but I am an entirely different person than what I was 25 years ago. I still struggle with a negative self-image at times, do not conform my will to God’s, etc., but I know God is there always to forgive me, to heal me, and help put me back on the right path.
I hope this helps.