There are substantial differences in the likelihood of staying married depending on ethnic group membership. In the chart below, there are estimates of the probability of women staying married by ethnic group. Black women are the least likely to stay married for 20 years. Only 37% Black are still in first marriages by 20 years. About half of White and Hispanic women are still married at 20 years. Asian women have the highest chance of staying married for 20 years. (79%).
For men, Hispanic men are the most likely to stay married for 20 years (62%) and about half of Black (53%) and White (54%) men staying in intact first marriages for 20 years.
The complete report on first marriages was produced by the National Center for Health Statistics.
There is considerable evidence that suggests that women with more education are less likely to get divorced. In this chart from the National Center for Health Statistics, you can see the percentages of women with various amounts of education and they likelihood that there marriages will last 20 years. You can see that women with a college education are much more likely to have marriages that last over 20 years (about 80%). There is a similar trend for men, but it is less dramatic.