I was married for five years. In the first two weeks I realized I was married to someone who struggled with alcohol. I did not go to Al-anon then.
A couple of days after our five year anniversary I finally went. It has been a lifesaver for me. We were together another four months after that, and then separated/working on divorce/divorced coming up on 17mths ago and I still regularly attend Al-anon.
It has helped me to sort out what is mine and what is not in this relationship, and honestly with others in my life who don't have substance abuse problems. It has helped me learn about addiction and alcoholism and not feel alone. For me the traits that got me into the relationship with an problem drinker were there before the relationship....and I am afraid of a repeat. Al-anon gives me the grounding in myself to know that I will be okay.
Not everyone finds a meeting that works right away. The common saying is try six meetings before you decide if it is for you or not. They all have a different feel.