my exAbf i don't think has admitted to himself that he is an addict probably more because of the perceived public stigma of what an addict or alcoholic is. he didn't even what to admit that he was a diabetic because that was a fat persons disease. he knows he use to take a lot of drugs, but i don't think he ever used the term "addict" even though he has been taking some sort of drug for over 20years.
like someone said...they are just in denial (even though deep down they know the truth) about how bad it is, because if they admit they have a problem, they might have to face it. and facing problems are hard and painful sometimes. best to just hide it and keeping drinking/taking drugs.