After 13 years together, Maggy Porter and Arlene Bronfman began to talk last June about marriage when New York State passed its Marriage Equality Act.

Until, that is, the New York-based couple visited their accountant.

What was supposed to be this way of expressing our love was going to seriously confuse our taxes, investments, estate planning, really all our finances, says Porter, a registered nurse. Our CPA is great, but even he seems pretty bewildered. We weren't sure how to proceed.

In the end, romance won out over finances, and Porter and Bronfman plan to marry in March despite the financial complications and expected tax hassles.

While marriage can save heterosexual couples a bundle, it could cost same-sex couples thousands of dollars in extra taxes and professional advice because the federal government still doesn't recognize the marriages.

Married same-sex couples must file separate federal tax returns but can file joint state returns in Massachusetts, New Hampshire, Iowa, Vermont, New York, Connecticut and the District of Columbia, where the marriages are legal, as well as in California, Illinois, New Jersey and Oregon, which recognize civil unions.

Filing taxes for same-sex spouses is much more complicated, more expensive and time-consuming, and there is very little guidance from the IRS or elsewhere, says Pan Haskins, a certified public accountant in San Francisco. This is still the Wild West of financial planning.

THE COST: UP TO $10,000

Haskins estimates same-sex couples could pay up to $10,000 extra in fees to file their taxes, but even the lowest wage earners with simple returns could pay an additional $1,000, most often for the extra time it takes their accountants to sort out the filings.

After that, the major consideration is whether or not you file in a common law versus a community property state, which legally determines how marital assets are divided. In common law states, same-sex spouses have the option of filing jointly or as single on their state return -- those are the same the options for heterosexual married couples.

Three of the nine states that have community property statues- California, Washington and Nevada- have legalized civil unions. Since 2010 domestic partners have been required to take into account each other's income in filing taxes.

There are two separate federal returns filed as single, but if I have wages and my partner has wages, the total of our wages is split and that is our income listed on the federal return, says Los Angeles-based tax attorney Wendy Hartmann.

We also then split federal withholding, deductions, mortgage and bank interest.

Particularly where one partner earns a significantly higher income than the other, this split can yield savings -- Haskins suggests up to $20,000 for a stay-at-home mom, for example. For other couples, however, it can push the spouses' income more quickly toward qualifying for the alternative minimum tax (AMT). So where you might have had one person before paying AMT, Hartmann explains, now there are two returns that qualify.

The IRS last year issued Publication 555, guidance for same-sex spouses filing in community-property states.

The document cleared up one widespread question: in situations where splitting incomes would leave one partner (normally the spouse with a lower wage) with a substantially higher tax burden, the higher wage earner can cover the difference without a gift tax penalty.

STATE POLICY DIFFERS

That is not necessarily the case in common law states, including New York, where one frequent pitfall is incurring a federal gift tax on transferred funds that exceed the annual limit of $13,000.

J.T. Hatfield Smith, a certified financial planner in Rockville, Maryland, suggests many same-sex spouses are usually better off filing as single rather than jointly. The biggest hurdle, he adds, Most people don't know what they don't know. Hiring an accountant or a certified financial planner, therefore, is usually a smart move.

For do-it-yourselfers, TurboTax and H&R Block, makers of two leading tax preparation software programs, have updated their offerings to help same-sex couples navigate filing two federal returns and the specific tax needs for their individual state.

New York State, for its part, advises couples do two federal returns - an official one and another a dummy return as if the pair were filing jointly. Not to submit but to use it as a worksheet so that you are bringing the correct income information onto a joint state return, says Ed Walsh, spokesperson for the state Department of Taxation and Finance.

Some same-sex spouses, however, are fed up enough to submit that joint federal return. Joining a nationwide campaign called Refuse to Lie!, Kate Kendall and her wife earlier this year decided to sign their federal tax return as married.

Why? Well, because we are married, Kendall, executive director of the National Center for Lesbian Rights, wrote in a April 18 blog post. After two years of still filing our returns as single, thus pretending that our marriage had never happened, I was done lying.

Couples who file federal returns jointly risk financial penalties and potential audit. Haskins reports, in her experience, the IRS has so far not challenged same-sex married returns. (IRS forms don't ask for gender identification.) She and colleagues have developed a disclosure form for their clients considering this move contrary to federal law. With caution, Haskins stresses, we are letting clients know that it could save them money.

Even without such complications, Hartmann calls the last two tax seasons in California an absolute nightmare though she sees the IRS requirements for same-sex couples as an important step in such relationships being recognized on the federal level. For East Coast taxpayers, she adds: I'd tell them it does get better.

--Consider holding assets jointly. Income or expenses from joint assets can be allocated all or in part to either owner's return.

--Income (e.g. interest, dividends, capital gains) may be shifted to the partner with the lower income, while deductions (e.g. mortgage interest, real estate taxes, capital losses) may be claimed by the partner in the higher income tax bracket. This could led to tax savings for both partners.

--Don't fall prey to the federal gift tax. Partners in common-law states currently can't give one another more than $13,000 per year without risking this 35 percent levy.

--Pay attention to taxes on health insurance. Unlike in heterosexual marriages, employer-based health coverage for same-sex spouses is not tax-exempt, and employers must report it as income to the IRS.

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