You need to get some legal advice ASAP! That way when he gets nasty and makes threats about the kids or money you will know where your stand regarding your rights. You also need to get out of there! Go to Centrelink and find out your entitlements. You may find you can afford to leave with some assistance. You may need to move to a cheaper area - outside the current school zone - but that doesn't automatically let XH "keep" the kids. Get to a lawyer (legal aid?) NOW!