L.G.
As much as I enjoyed visiting Australia, the cost to travel there was huge. Make sure you consider the travel costs for you and/or your family to be able to stay in touch.
Affordability is always a personal thing. Just as there are happy people here in the U.S. living on less than $40,000 a year, there will be happy people there living on much less than $100,000. Can you AND your husband regularly say "no" to yourselves in order to maintain financial security and still be content? That is the real question.
If you are the adventurer type, this could be awesome!