Hi!
I have spent 3 h going through forums and havent found an answer.
I found from Immi.gov.au website a following details:
Fact Sheet 35 - One-Year Relationship Requirement
Certain people wishing to settle in Australia permanently are required to be in a relationship for at least one year before they can apply.
The one-year relationship requirement applies to people who are applying to settle in Australia as the de facto spouse or interdependent partner of an Australian sponsor. It also applies to the de facto spouses of

permanent

or Student visa applicants.
457 goes belongs under temporary visa.
My boyfriend and myself have been living together for a year, but the paperwork only shows 8 months, so I think we would fail to prove that we are de facto for a year.
I am really hoping that the above from immigration wepage shows that we only have tp prove that our relationship is de facto.
Thanks,
Mari