This is where it gets interesting.
Section 32DA (Meaning of Defacto Partner) of the AIA provides:-
“(1) In an Act, a reference to a de facto partner is a reference to either 1 of 2 persons who are living together as a couple on a genuine domestic basis but who are not married to each other or related by family.
(2) In deciding whether 2 persons are living together as a couple on a genuine domestic basis, any of their circumstances may be taken into account, including, for example, any of the following circumstances—
(a) the nature and extent of their common residence;
(b) the length of their relationship;
(c) whether or not a sexual relationship exists or existed;
(d) the degree of financial dependence or interdependence, and any arrangement for financial support;
(e) their ownership, use and acquisition of property;
(f) the degree of mutual commitment to a shared life, including the care and support of each other;
(g) the care and support of children;
(h) the performance of household tasks;
(i) the reputation and public aspects of their relationship.
(3) No particular finding in relation to any circumstance is to be regarded as necessary in deciding whether 2 persons are living together as a couple on a genuine domestic basis.
(4) Two persons are not to be regarded as living together as a couple on a genuine domestic basis only because they have a common residence.
(5) For subsection (1)—
(a) the gender of the persons is not relevant; and
(b) a person is related by family to another person if the person and the other person would be within a prohibited relationship within the meaning of the Marriage Act 1961(Cwlth), section 23B, if they were parties to a marriage to which that section applies.
(6) In an Act enacted before the commencement of this section, a reference to a spouse includes a reference to a de facto partner as defined in this section unless the Act expressly provides to the contrary.”