The authors of What is Marriage? One Man, One Woman, a Defense write in National Review Online that the conjugal view of marriage leaves everyone just as free to pursue companionship:

"...Now then, the supporter of same-sex marriage asks, shall we deny all this [the benefits of marriage] to the thousands of men and women in same-sex relationships?

We shouldn’t, and we don’t. Whether or not these companionate ideals are all equally healthy to seek, all in one bond, and all specifically in marriage, the general desire that animates them — to know and serve one who knows and serves us — is the desire to love. No aim is nobler.

But traditional marriage law denies these companionate ideals to no one. It does not discourage anyone from seeking them. Its more specific view of what makes a marriage can even liberate us for emotional intimacy in other bonds. And even if companionate bonds are impaired if deprived of public status, it does not follow that they require legal status. Remarkably, then, one of the most common and powerfully felt objections to conjugal-marriage policy is also one of the easiest to answer. The law simply has much less to do with this than people commonly suppose. We can unpack this all."