Normally under Australian succession law marriage cancels a will (that is revokes in legalese) – unless the will was made in contemplation of marriage.
In addition to marriage, legislative amendments in some states/territories such as South Australia, Tasmania and the ACT, now provide for people contemplating entering into a registered relationship or partnership to make arrangements in their will. However the legislation on this topic of making a will when contemplating marriage varies across the jurisdictions.
It is important to check what the provisions are for where you live if you are planning on making a will ahead of getting married or entering into a relationship. Specific legal advice and assistance should be sought. A brief look follows.