If you’re married but file separately from your spouse, you’ll be required to use the same deduction method as the other party. This means if your spouse chooses to itemize, you too will have to itemize your deductions and you will not qualify for the standard deduction.
You may need to claim a separate returned with itemized deductions that you paid, whether on your own or jointly with your spouse. There are some expenses, like those paid from a designated fund, that are only deductible by the person who actually paid the expense. In situations where the fund is not personal, but is instead a community fund, then you’ll be able to deduct these expenses based on whether not you live in a community property state. In a community property state, few deduction amount is determined by splitting the expenses equally between you and your partner.
If you file your tax returns separately from your spouse and do not live in a community property state, you’ll only be able to deduct expenses that you actually paid. If you and your spouse own a joint checking account, and expenses were paid with money from that account, then both you and your spouse are considered to have equally paid. The only exception to this is if you can prove your claim to the account.
Community Property State
For medical expenses that come from a community fund in a community property state, married couples or those who are registered domestic partners of Nevada, Washington, or California will have to divide the amount of the expenses in half. On your tax return, you’ll only be able to deduct half the funds if you file separately. Medical expenses that were paid from a private fund are only able to be deducted by the person who paid, regardless of whose expenses they were. Same sex married couples in California must adhere to the same rules.