My husband and I noticed the same thing! We've talked about it many times, wondering why so many divorces occur at the magical number of 10 years. The discontent had to have been brewing for some time before that. I have a feeling that these couples are looking at the 10 year milestone, and instead of preparing to celebrate 10 years of successful marriage, are horrified that they are hitting 10 years in a marriage that makes them unhappy. As to why so many choose to divorce rather than stay the course, the reasons are myriad. I agree with you that it's a shame that, at least in western nations, the divorce rate is still so high.