When a marriage or de facto relationship breaks down, it is common for too much emphasis to be placed on the division of assets. Instead, the welfare of the children should be the primary concern for all parties involved.
Issues relating to all children fall under the Family Law Act 1975 (Commonwealth). They are dealt with through the Family Court, the Federal Circuit Court (Federal Magistrates Court) or the Local Court. These courts cover issues relating to child custody laws, residence of children and ongoing financial support of children. It doesn't matter whether the parents are married, de facto, same sex couples or adoptive.
In any dispute concerning child custody and where children will live, the starting point is Section 65E of the Family Law Act 1975. There are normally two separate hearings, an interim hearing and a final hearing.