@jonathan7082 This seems to be a good read. https://www.gotocourt.com.au/family-law/de-facto-relationships/
<b class="Bold">De facto relationship definition</b>
A de facto relationship is a relationship in which a couple lives together on a genuine domestic basis. This definition is the same across Queensland, New South Wales, Victoria, Northern Territory, South Australia, Western Australia, Tasmania, and the Australian Capital Territory.
Couples who are same sex or opposite sex are included in the definition of de facto relationship under Australian law. A couple by marriage or who are related by family cannot be considered to be in a de facto relationship. <b class="Bold">However, if a person is legally married they can still be considered to be in a de facto relationship with another person they are not married to.</b>
A person would not have a de facto partner unless they have lived together as a couple for two years without separation. Therefore, the length of time to be considered de facto is two years. However, if there are children or substantial contributions to joint property, exceptions are made to this rule.
De facto relationships are governed under the Family Law Act 1975. This means that your rights regarding property settlement, child maintenance and separation are dealt with under the Family Law Act 1975. De facto relationships in Western Australia are governed by the Family Law Act 1997 (WA), however.