I don't think you can pick apart certain actions and say "this is codependent" and "this is not." It's an overall pattern of relating and interacting.
I paid my husbands taxes for the last 4 years of our marriage. I could argue that it was in my best interests to do so because the IRS would come after me because we were married. But, the overall pattern of our marriage was one of him being irresponsible and me 'taking care of it' when his irresponsibility caught up with us. So, whether the paying of the taxes was codependent or self-preservation was not the question. The question was 'why am I in a marriage with someone I have to protect myself from?'
L