Marriage will revoke any Will you have made prior to that marriage BUT divorce does not necessarily revoke a Will. In every state except the Northern Territory and Western Australia the law states that your Will is either revoked when you divorce or the section of your Will relating to your former spouse is considered null and void. It is absolutely vital that you write a new Will after you divorce to ensure you do not die intestate.
If you are in a relationship with another person but not yet married, you can write your Will, it will be valid up until you marry. Marriage revokes any Will. If you want to write a Will that is valid now and after you marry, you can do this by including a clause written into your Will that the Will is made in ‘contemplation of marriage’. This will mean that the Will you make now is valid and continues to be valid even after you marry. The Online Australian Will Kit has included this clause in the Will Form for anyone that wishes to make their Will now, and it continue to be valid even after you marry. The Online Australian Will Kit discusses this clause in more detail and contains important instructions on how to fill this clause out correctly.
The most important thing to remember is that when your circumstances change, so should your Will.