Fortunately, it’s an intriguing issue, and researchers continue to investigate the question. Recently, The Journal of Family Psychology published a study by Sigan Hartley, in which she looked at 406 families of autistic children, as well as an equal number of parents of typical children. The study found that divorce rates were equal up to the child's age of eight, after which time the parents of autistic children were more likely to divorce. The study found a 23% divorce rate for the autistic families, compared to 14% for the typical families, still a far cry from the often reported 80% rate. Hartley suggests that the difference in rate found between this study and the Kennedy Krieger study was due to the age differences of the children. The Kennedy Kreiger study, which found equal divorces rates regardless of the presence of autistic children, looked at children under 17, while Hartley’s study included children into middle age.
Clearly, this is not a simple question, and more research will give us more details. But, the good news is that most families do manage to stay intact, regardless of their children's diagnoses.