Welcome, I'm so glad you've found SR.
You say you've never opened up to any one about his problem, well hold on to your hat. You're soon going to realize there's a world of people out there just like you. I don't think there is a family on this planet that hasn't been touched by addiction.
One of the great things about Alanon is that no one will ever tell you to "divorce him"! As a matter of fact, some people are initially thrown off at how little advice they give at the meetings. It's primarily a place for support, but that support can be life changing. SR, of course, is amazing as well. There nothing quite as lonely, and confusing as living with an addict, and the only people who understand are those who have been through it.
Like Hopeful4 said: "Sorry for what brings you here, but glad you are here."
((( Hugs ))))