'Spousal Maintenance' is money paid by one spouse (the paying spouse) to the other (the receiving spouse) in circumstances where the receiving spouse is unable to support themselves 'adequately' following separation.
In determining whether or not spousal maintenance is appropriate, the Court will consider the following:
Whether the “threshold” is met (i.e. that there is a 'need' for one of the parties to be financially supported by the other);
The capacity by the other party to support the first party for a period of time.
The matters in Section 75(2) of the Family Law Act 1975.
The extent of support required (what is 'adequate' in the circumstances) and the amount of time maintenance is required to be paid for.
What must be remembered, however, is that the Court is not required to ensure that either party has the same standard of living that they had before separation.  It only has to be reasonable in all the circumstances.