How do I get my husband to agree to counseling?

My husband and I have been married for 18 years with 2 children, 14 and 17.  He has been on ADD meds for 6 years and in the beginning they helped. But over the past 2-3 years his symptoms have become progressively worse.  His doctor just gives him a prescription without any counseling to go along with it, so I don't believe she knows how bad he has gotten.  He is not focused, gets very angry very fast, is drinking a lot, seems disassociated with me like he is in his own world.  I feel our marriage disintegrating and I have become emotionally vacant to help with my pain and loneliness. How can I get him to agree to go to counseling without him blowing up and feeling like I am ganging up on him? I don't even know how to bring the subject up.  He doesn't think there are any issues with his ADD.