avengers_search | Fic: Tony and Steve on gay marriage

So I've been looking everywhere for this one fic which involves Tony talking to Steve about marriage - I think it was as a reaction to gay marriage (maybe Obama speaking out) - and basically quoting a movie about all the reasons marriage as an institution is obsolete and unnecessary (something like, people in the past had to stay together for economic reasons etc.). I don't even really need to find the fic, knowing what movie it was from would be enough. ;)

Does that sound familiar to anyone? I'm pretty sure I read it on AO3 and I've looked around there, unsuccessfully. The lack of tag filtering didn't really help either.