This isn't my experience, it is the ES&H of my alanon group, so take that with a pinch of salt (as its second hand)
The majority of long-term members in my Al-anon group, who were there because of an alcoholic husband/wife were still with their husbands/wives and their husbands/wives were in recovery. Of these those, most had come to the rooms after their AH/W had started AA. One had thrown AH out with the stipulation that he had to attend AA, and it has aparently stuck for 20-odd years. A couple of others had done the same and it hadn't stuck, a couple more were with their AH's who were not in recovery, many newcomers came, grew, left or were left by their A's and then stopped coming....and then there were the parents and children of alcoholics.
I wish there were a way of predicting which group we would end up in (and how long that would last).