Wall Street Journal: Same-sex couples can get married in five states and the District of Columbia—and in New York starting July 25. But the happily-ever-after part doesn’t necessarily extend to their personal finances.

Such couples still can’t file a joint federal tax return, share retirement benefits, shield each other’s assets from estate taxes or benefit from many other tax breaks provided through federal law.

As a result, same-sex couples who marry have to stay on guard, doing even more financial and legal planning, in some cases, than those who don’t choose to tie the knot.