In early Celtic Ireland, grounds for divorce included sexual impotence due to gross obesity, telling tales about your love life, or being a thief. There was also a virgin-price that guaranteed the wife’s purity. It’s also interesting to note that if two people of unequal rank wanted to marry, the person of lower rank was responsible for the financial burden. We can assume this was meant to keep Celtic nobility from “marrying down.”
In 1937, divorce was banned under the Constitution, so you couldn’t legally dissolve your marriage on any grounds, including wife-beating, unfaithfulness, enduring decades of mental torture, etc. It’s ironic that we can’t say that the 1937 ban put us back in the Dark Ages, as in many ways the Dark Ages were much more enlightened.
The Fifteenth Amendment of the Constitution of Ireland removed the constitutional prohibition of divorce. It was effected by the Fifteenth Amendment of the Constitution Act, 1995, which was approved by referendum on 24 November 1995 and signed into law on 17 June 1996. The Divorce Act requires that the couple must have lived apart for at least four of the five years before proceedings are issued. During the referendum campaign, Government ministers seemed to suggest that a couple could be living apart if they were under the same roof but not sleeping together.
Same-sex marriage has been legal in Ireland since 16 November 2015. A referendum on 22 May 2015 amended the Constitution of Ireland to provide that marriage is recognised irrespective of the sex of the partners.