In 1916 in Allegheny County, there were issued 12,259 marriage licenses; and the same year 1,256 applications were filed for divorce. During the same period 725 divorces were granted and forty-six refused. This means that for every ten weddings solemnized in Allegheny County a divorce was applied for; and for every seventeen couples married, there was one divorce.
Domestic instability is fast becoming an epidemic social disease among us. It is nation-wide. In the thirty years from 1870 to 1900 there was a decrease in the United States of over ten per cent. [sic] of marriages in proportion to the population of the country. This is alarming, even if the reason is economic. But this is not nearly so bad as the fact that in the United States in 1910 there were granted 91,000 divorces. Divorce is the most portentous problem that confronts society to-day."
FamilySearch has divorce records for the following states: Arkansas, California, Colorado, Connecticut, Florida, Idaho, Minnesota, Texas, Washington, and Wisconsin. In addition, you may find divorce decrees attached to marriage license applications.
For example, my great-aunt Ruth Huber's 1940 marriage license application in FamilySearch shows that she was married once before and that the divorce date was November 17, 1934. That one page has a lot of information including details about her second husband, her occupation and residence, and the names of her parents. The next pages contain images of the certified copy of the divorce decree, showing that the Court found that her first husband "committed wilful [sic] and malicious desertion, and absence from habitation of the injured and innocent spouse...without a reasonable cause, for and during the term and space of two years."
You've probably heard it before, but this is a reminder: always look at the pages before and after your ancestor's record. You just may find additional details.