Here's an interesting article, It Ain't Easy Being Superman, that compares Superman stories to the role of the United States as a world power. It concludes:
It’s not too late to rethink this. Maybe we can learn something from Haiti, to tap into our country’s instinct to help a neighbor in need, and think more broadly about our long-term relationship with countries that could really stand some bootstrapping assistance. If Superman, Lois, and Clark were real people, their story would have ended up in tragedy without some change in trajectory. We have the opportunity to make that change in our own world, if we would choose it.
Throughout, the writer refers to Superman in the past tense, as indicated above. Nothing against her, but in several versions of the story, Superman/Clark and Lois do change their trajectory, and they're married in current comics continuity. I know, I know, she's using the relationship as an analogy for foreign policy. Still, it brings to my attention that the common conception of Superman still has the love triangle aspect to it, despite any number of shows, comics, and movies. That's how it exists in the minds of a lot of people.
Here's a consideration of the marriage, from Sequential Tart (it's the last section of the page, down a bit):
Especially by bringing in Lois's extended family, the marriage emphasizes the "Superman family" approach to upholding the commonweal in contrast to vigilante crime-fighting. This places Superman's adventures in a larger social context and goes against the grain of the lone wolf hero figure. (Batman has his "family" as well, one that is more wary, even of each other, than Superman's.)