https://phys.org/news/2018-07-unreasonable-behaviour-common-ground-divorce.html

The Act made the irretrievable breakdown of a marriage the sole ground for divorce, which can be established by 'proving' one or more 'facts' - though the 'fact' is not necessarily the cause of the breakdown.

In addition to 'fault-based' facts, which imply blame: 'unreasonable behaviour," adultery and desertion, the Act introduced two new innovative, 'no-fault' separation facts; one of 2 years' separation with both parties agreeing to divorce, and the other of 5 years' separation without agreement.