It is exciting to see the New England states recognizing the fairness of allowing gay folks to marry. It is a huge step and where people can marry they also inevitably will pay taxes and some of them will later divorce. In these areas much inequity still remains.
The Defense of Marriage Act (DOMA) impacts the income tax and divorce tax status of gay couples regardless of whether or not they are legally married.
They cannot file federal income taxes as married filing jointly; when, and if, they divorce any transfers of property between them are taxable events, as they are not for heterosexual couples, and there is no deduction for alimony.
All of these are costly, but still it is terrific to have another state recognize gay marriage.