I find that I do this in intimate relationships as well as friendships.
Not always with alcohol use as their crutch but often with at least one addiction in process.
As I have gotten healthier I have found healthier relationships to get myself involved in.
I had to ask my therapist once "what is unhealthy alcohol use." You know it matched up with what I thought but I was so surrounded by it, and had "heard" so many people with struggles tell me their version of it that I did not always believe myself.