The Internet's not what it used to be. Books mostly hidden online, scans on archive.org not searchable. This is the best I've found so far, from “Feminism, Liberalism, and Marriage” by Clare Chambers, page 5, 4th paragraph:
“…if marriage no longer disadvantaged women practically, would it matter if they were pressured to enter it symbolically? We might have a number of autonomy- and diversity-based objections to such pressure, which would apply to both women and men. But one way in which pressure to enter into even reformed marriages might particularly harm women (and thus be of particular concern to feminists) is through the simple fact that marriage has historically been an extremely sexist institution. Even if these historical oppressions have been reformed, such that wives are equal to husbands in all areas of law, marriage remains an institution rooted in the subjection of women. As Toerien and Williams argue, “marriage remains thoroughly tainted by being a long-standing buttress for the patriarchal domination of women.” " 

 Just don't tell this to modern LGB who seem to think that being able to participate is a straight misogynistic institution is their most important human right