Meggy, Al-Anon is for you. It is for you to get better and to have your own recovery no matter if he is drinking or not. You could try telling him you are going because you have a lot of anger and resentment about his drinking and that is not good for either of you and that drinking is his choice not yours and that is something you are struggling with because you don't want to be angry with him.
It points no fingers, let's him decide whether he wants to drink or not and is easy to remember because it is true.
In addition, that is exactly the kind of stuff you will learn at al-anon.
Your friend,