If you want to continue the relationship with him, then you need to go to Al-Anon meetings. Check AA's website for info on the closest AA and Al-Anon meetings. If you have a local newspaper they often list meetings. One thing you will learn in Al-Anon meetings is that you have no control over his drinking and he--and only he--can make the decision to stop drinking. Al-Anon will help you cope with his drinking and will show you how not to be an enabler.
I also think your idea of an intervention is a good one. Again, Al-Anon can help with info on how to properly do this.