It depends. Generally, filing jointly will give you a bigger refund or less taxes due. When you file separately, your tax rate is higher and you won't be able to claim certain deductions or credits that you can when you file jointly. Here is more information on filing jointly versus separately:
https://ttlc.intuit.com/replies/3288477
Here are instructions to file an injured spouse form if you decide to pursue this route -- note the section on how to file if you have already filed your tax return:
https://ttlc.intuit.com/replies/3326788
