For same-sex couples living in Massachusetts, California, Connecticut, New Hampshire, New Jersey, Oregon, and Vermont, either same-sex marriage or a reasonable facsimile is now a reality. If you live in any of these states, you and your partner have a decision to make that same-sex couples have never had to make before: whether marriage is right for you.

A few other states -- Hawaii, Maine, Washington, D.C., and Washington State -- have domestic partnership laws, but they offer limited rights that don't really approximate marriage. Still, for folks living in these and other states, it's never too early to think about what you might do if new relationship options became available where you live.

Factors to Consider
Here are some things to consider as you think about how you want to structure your relationship.

Having children. In most cases, if you have children or hope to raise a family, getting married is probably the right choice. Both partners in a married couple have the same rights and responsibilities to raise and support children of the relationship, and in a divorce both can seek visitation and custody. If one parent dies, the other one steps right in as the primary legal parent. It's pretty difficult to make these sorts of arrangements absent a legal marriage or a second parent or stepparent adoption.

Jointly owning property. Marriage isn't a prerequisite for owning property together, but if you get married, in most situations your property will be jointly owned regardless of who paid for it. This is the reverse of the presumption that applies to unmarried couples. Getting married may be the most efficient way of establishing a property merger. If keeping things separate is more to your taste, you will have to sign a prenuptial agreement to avoid the joint ownership presumptions of a legal marriage.

Splitting up property. In most states, each married spouse's earnings are owned by the two of you, and, if the marriage breaks up -- regardless of who's at fault -- you each generally get half of everything you've accumulated. By contrast, if you are unmarried, your property is co-owned only if you have an agreement to that effect, and likewise for debts and obligations. Divorcing spouses are also entitled to seek alimony if the marriage doesn't last, without the need for any explicit contract providing for post-separation support.

Formalities. Every marriage requires a formal ceremony, and every marital separation requires some kind of formal court action -- and quite often the help of a lawyer. Unmarried couples can break up informally, on their own terms.

Inheritance and death taxes. Without a legal marriage, a couple needs to sign several agreements to create even a partial framework of protection in the event of death, and certain tax benefits are forever denied to unmarried couples.

If you are married, however, the surviving spouse generally inherits all the property if the partner dies without a will. (Laws exempting married couples from inheritance taxes and gift taxes don't yet apply to same-sex couples, because the federal government does not recognize same-sex relationships even if state law provides for marriage or marriage-like benefits.)

Transfer taxes. In theory, transfers of property upon dissolution of the relationship are tax-free for legally married couples, but not for unmarrieds. It's unclear yet how these rules will apply to same-sex couples, because of the federal government's refusal to recognize same-sex relationships.

Government benefits. Marriage can bestow a bevy of important benefits, including military or Social Security benefits, health care benefits, and nursing home coverage. Marriage may also qualify you for unpaid leave from your job under the Family Leave Act. However, be aware that a married person's income could disqualify a spouse from receiving Social Security, welfare, or medical benefits.

Immigration. A legal marriage is the only reliable method of providing a foreign partner with the privileges of immigration to this country if the person doesn't qualify under work or other provisions of the Immigration Act.

However, again because the federal government does not recognize same-sex relationships, this benefit is not yet available to married same-sex couples. In fact, couples in which one partner is a nonresident are advised against getting married or entering a civil union or domestic partnership, which could threaten their visa status in some situations.

Making the Decision to Marry or Not
If you need to make a decision about how to structure your relationship, first decide whether you fall into one of the got-to-marry or better-not-marry situations. Raising kids or facing a serious illness, for example, generally favors a marriage (unless it disqualifies you for Medicaid ), whereas getting saddled with your partner's debts or losing Social Security benefits probably favors a no vote.

If you don't find yourself at either extreme, take a close look at the marital property rules for your state, evaluate the benefits and burdens given your personal situation, and get a good sense of what being married would do for you financially.

Then, consider whether being married feels right for both of you emotionally. If the answers come back positive for both of you, then proceed, but consider creating a prenuptial agreement if any aspect of the traditional marriage structure doesn't meet your needs. If the impact of marriage feels unduly negative for one or both of you, however, maybe you should hold off.

To learn more about issues facing same-sex couples, get The Legal Guide for Lesbian & Gay Couples by Hayden Curry, Denis Clifford, and Frederick Hertz (Nolo).