There are two optios:
Prepare your tax return, filling as 'married filling jointly' and either
1. File for ITIN for your husband withyour tax return. OR
2. Do the taxes as you would , married filling jointly, if you have to pay anything - do pay- and file extension. Once he gets here and you get the SSN, file then. You have until Oct 15, 2015 to file under the extension.
If you file with ITIN then you will have to submit to IRS a request to recognize EIC http://www.irs.gov/Individuals/Individual-Taxpayer-Identification-Number-%28ITIN%29-Reminders-for-Tax-Professionals , which is ok but it's much easier to file extension and go without the ITIN then to file, and then file with IRS to recognize the earned income credit.
If you file married filling separately, the tax bracket will be higher and you will pay more in taxes.
I am a Bookkeeper and this is what I do for living.
