I went through several attorneys. The Judge would NOT even hear the case until I hired a lawyer to protect the CHILDREN's interests. I hired an attorney for the children and I continued to represent myself. The reason I went through so many attorneys is because I had to keep firing them when they did things I SPECIFICALLY told them NOT to, such as speaking with his attorneys without me being a party to the conversations.
As CJane explained, there is a huge difference between USE and ABUSE. Another huge factor is money. Without a well documented history of not only alcohol and/or substance abuse AND documented proof that the abuse has and will continue to adversely affect the children, the "proof" has to be bought in the form of expert witnesses, psychological evaluations, home studies, private investigators and so on. None of those things are cheap. I had to cash out my retirement, drain my savings, max out my credit cards, sold everything of any value that I owned and borrow money on top of all that to finance a divorce, that went on for 2+ YEARS, in which the ONLY thing I ended up with was my children.
If it's not something that you can AFFORD to follow through with, there's no point in even starting.