taken from TNA research guide
'From 11 January 1858, the new London-based Court for Divorce and Matrimonial Causes heard all divorce and matrimonial cases (such as restitution of conjugal rights, legitimacy, protection of earnings). In 1873 it was reformed into the Probate, Divorce and Admiralty Division of the Supreme Court of Judicature.The real opening of divorce to all classes took place in the 1920s, with the extension of legal aid, and the provision of some local facilities. In 1922, ten assize towns were named as suitable for the hearing of certain kinds of divorce. From 1927, petitions could also be filed in 23 district registries instead of solely at the Principal Registry in London, while cases could be heard in 18 assize towns as well as in London. This option proved increasingly popular: within 10 years nearly a quarter of all suits were started at district registries of the Supreme Court. The county courts were finally able to hear divorce suits in the late 1960s. Most divorces now take place at county courts.'
Pre the 1920s there were no divorces in the provinces. As I stated you could only be divorced in the High Court in London.
Lawrence Stone's book 'Road to Divorce A History of the Making and Breaking of Marriage in England 1530-1987' first published 1990 is the best book and most often quoted on divorce.
Examples of his figures for divorce decrees are
1861 141 (divorce rate per 1,000 married couples was 0.04)
1906 546 (divorce rate 0.09)
1945 15,600 (divorce rate 1.4)
1985 160,000 (divorce rate 13.4)
I've tended to give peak years between the wars.
Have you a copy of your great uncle's marriage certificate in 1909? What are the details? Does his wife definitely give her status as a divorcee?