Dear jaja,
Have you already formalised your property settlement after you separated with an agreement or court orders?
Either party to a de facto relationship may bring an application for Property Settlement at any time after separation (this is best done straight away). Proceedings for a property settlement (court application) must be brought within 2 years of your separation as a de facto couple. If you don't commence property proceedings within these limits you may lose your rights. If a property settlement is not reached prior to this time limit, you may still be able to bring an Application for Property Settlement "out of time" with the court's permission, however I don't know what your chances would be 4 years outside of the time limit.
As has been stated many times in this forum, there are no rules of 'entitlement' per se when it comes to property division and settlement orders. While it is true that a court has power to split a party's superannuation, it will only do this it deems it fair and just having regard to all the circumstances. A court goes through a process of determining what is fair and just based on all the circumstances of each party including their contributions to the assets and their financial needs.
Court applications can be expensive and you will require legal advice and perhaps representation, in addition unless you can provide compelling evidence of why you should be allowed to make an application for settlement 4 years outside of the normal time limits the court will not hear your application. I would weigh up whether the cost is worth what you will receive out of it.
This is why it is important to seek legal advice immediately upon separation.
Refer to these threads for more info:
Can Ex Spouse Claim Assets Years After Separation?
http://www.lawanswers.com.au/threads/de-facto-property-settlement-finalised.895/