You could drive a truck through the holes in rohitcuny's post, above. It doesn't take same-sex marriage to create economically driven marriages -- that's one of the prime reasons historically for marriage. In the above example, it wouldn't even work unless the tax breaks referred to are state ones -- federal tax code does not recognize same sex marriages even in the states where it is legal. Until the federal government equalizes its treatment of same sex versus different sex marriages, that won't change.