For a married couple to file separate, is the worst and most costly way to file tax-wise. When you file seprate returns, both of you *AUTOMATICALLY* disqualify for deductions and credits you would get if you file joint. No EIC, no education credits, and a number of others.
On top of that, if one of you itemizes deductions, then both of you must itemize deductions even if the itemized deductions of one of you is ZERO. Likewise, if one takes the standard deduction then you both have to take the standard deduction even if the itemized deductions of one of you is greater.
If you're wanting to file separate because of student loans, then one of the credits/deductions you lose is that you can not deduct student loan interest. So what you "save" in lower loan payments you will pay in higher taxes and more interest.
