Filing a joint return is generally simpler for couples, and most of the time will produce a lower tax bill than if the couples filed their returns separately. However, there are some cases where splitting your income may make financial sense.
If you are on an income-based student loan repayment plan, opting to file separately can reduce your monthly bill, as they generally use your adjusted gross income to calculate your payment. Filing separately means that only the borrower's income is taken into account, rather than the total household income. That can be incredibly beneficial to a person paying student loans, so it may be worth the consideration to file separately.
Spouses must use the same method of deduction. For example, if one spouse choses to itemize, the other partner must as well. Additionally, some credits and deductions, such as the credit for child and dependent care expenses, Earned Income Tax Credit, Adoption Credit, education credits and student loan interest deduction, are not available to couples who file separate returns.
Filing separately is not the same as filing Single. Only unmarried taxpayers are entitled to use the Single status, as there are different tax brackets available to those who file single as opposed to married, filing separately.