Since your marriage earlier this month, have you completed a new Form W-4 and given it to your employer in order to increase your withholding allowances, and thus, your net take-home pay? If not, then you and your husband each need to do that ASAP.
You cannot technically obtain a refund of the excessive amount of withholding tax you paid during the first three quarters of this year based on your having to report 1/2 of your domestic partner's gross income under California community property law, see http://taxprof.typepad.com/taxprof_blog/2010/06/irs-income-of-.html (like a married person filing a separate return). However, you can adjust your tax withholding for the remainder of this year to offset most (if not all) of the earlier excessive withholding and reflect the fact that you will file a joint income tax return for 2013.
It should not be very hard for the payroll department to adjust the amount of your tax withholding in order to ameliorate the excessive amounts withheld earlier this year. Even if you and your husband may not have any dependents, there is no reason why you should be limited to only 2 withholding allowances. I would ask a bookkeeper/accountant from your company's payroll department how many withholding allowances you need to claim in order to reach your "target amount" for each payroll period for the rest of 2013 in order to equalize the earlier excessive tax withholding for the first three-fourths of this year. In addition, keep following up with the bookkeeper/accountant in the payroll department to ensure that they have updated and processed your new Form W-4. Whatever you do, be persistent, since "the squeaky wheel gets the oil."
Good luck in resolving your tax issue. Congrats on your recent nuptials!
The answer to this question does not establish an attorney-client relationship. Moreover, this attorney is licensed to practiced law ONLY in the State of California. Answers to questions from users in other jurisdictions or states are meant to provide only general information. Users should contact a local attorney in their jurisdiction or state to address their specific tax issue.
If you are talking about Federal Income taxes being withheld, then ultimately, when you file your income tax return (presumably Joint with your new husband) you will report what ever is the correct amount of total income which will, with your new filing status, create the correct tax and if you overpaid you will receive a refund at that time.