We already filed and received our money but i want to file separately even though i dont have a job

What?  You already filed a joint return and received a refund?  But now you want to file a return?  But you did not earn any income?  Please explain what you are actually trying to do.  Now that the filing deadline for 2016 is over, it is too late to change a joint return to married filing separately.

When only one spouse works, it is still allowed for the spouses to file married filing jointly, and this almost always result in lower taxes.

 If you have already filed jointly, it is too late to file an amended return to change it to separate. The deadline for that is April 15. 

If you have no separate income, you would get nothing back anyway.    And if your spouses tax refund is being held back for debts,  filing separately or filing injured spouse form will not help you get any of that refund back because you don't have income.