Whichever method your spouse choses for taking deductions, you’ll have to follow suit, even if you file separately. If one of you opts to itemize your deductions, the other will not qualify for a standard deduction and ill also have to itemize.
It possible that you can claim a separate return with itemized deductions that you paid, either separately or jointly with your spouse. Certain expenses that were paid from a designated fund, like medical expenses, are only deductible by the person who paid the expense. If the fund from which money was used to pay is not personal, and instead is a joint or community fund, your ability to deduct these expenses is relevant to whether or not you live in a community property state. If you do, the qualifying deduction amount for expenses paid from funds is split equally among you and your spouse.
If you don’t live in a community property state, and chose to file separate returns, you are only entitled to claim medical expenses that you actually paid. If you own a joint checking account with your spouse, and used it to pay for expenses, unless you can prove your claim to the account, expenses will be considered equally paid among you and your spouse for tax purposes.
What is a Community Property State?
Married couples who live in a community property state, or registered domestic partners in the states of Nevada, Washington, or California, who have paid medical expenses from a community fund will have to divide the expenses in half. When filing a separate return, you’ll have to deduct only half of the funds. If medical expenses were paid from a private fund by one spouse, only that spouse can deduct the expense. The same rules apply to same-sex married couples in California.