“Should it be unlawful for an employer or the government to pay survivors benefits to a spouse and not to any other kind of partner? “
No, it should be a matter of agreement between employer and employee. Tha government should have no role in this.
Gay activists want the government to deprive employers of the choice to which you refer. That's what “gay marriage” “domestic partnerships” are all about. They want to keep us from treating a homosexual couple differently from a married couple which makes it impossible to express disapproval of the former in any concrete way. That's what the debate is about. Are you with the gay lobby and for making government larger and more coercive or are you against it? The choice is stark.