Here is what you do:
1) If he gets it, tell him to have fun. Prepare to be dumped, but instead, dump him telling him Australia isn't for you and you're not interested. You look like the dumper and now he looks like he was running away from a broken heart.
2) If he doesn't get it, lose sh*t on him for trying to get it and not planning it with you, dump him anyways and send him packing. Anyone who would pull this stunt deserves to be dumped.
Either way the relationship is over, but both ways you come out a winner.
"All is fair in love and war." - Francis Edward Smedley