Filing After Divorce or Separation
For tax purposes, your marital status is determined as of December 31st of the tax year. Therefore, if you are legally married as of that date, your filing status choices are generally married filing joint or married filing separately. While filing a joint return is usually easier, it can have drawbacks if the other party does not cooperate in assembling the information necessary, and both spouses will remain separately liable for the income and deductions of BOTH parties reported on the joint return.
One exception: If you do not live together, nor mingle your finances, for the last six months of the tax year, AND you paid more than half the cost for the year of keeping up the home in which you and your dependent child lived, you can generally file as Head of Household.
If you live in a community property state, be aware that your state law will determine what allocations need to be made between your separate returns for the period of time you were married.
For a divorce decree after 1985, the custodial parent is generally permitted to claim the dependency exemptions for the children, regardless of who actually provided most of the support. If the
custodial parent agrees that the other parent should be able to claim the child, he or she must sign a Form 8332 which gets attached to the non-custodial parent's return for the year.