Well, part of the issue of Superman/Lois/Clark triangle comes straight from the comics and the Superman movies (including Superman Returns) are based on the ideas given in the pre-Byrne reset comics.
Lois Lane is in love with the proud Kryptonian Kal-El who can barely give her the time of day. To have a link with humanity, the Kryptonian masquerades as a human - his version on a human, flawed and weak. (Kill Bill didn't have it all wrong.) And of course Lois can't give the alter-ego the time of day. It's a triangle that's meant to be eternal written for an audience for whom anything more romantic than a peck on the cheek is sacrilege.
Then in 1986, the entire psychology of Superman is turned upside down. Clark Kent is a baby found in a spaceship and raised on a farm in Kansas. He grows up a healthy, normal child until he reaches his teens when all hell breaks loose - Clark Kent discovers he has powers far beyond those of mortal men. As an adult, he discovers he is from a planet he knows almost nothing about.
It's Clark Kent who has to invent Superman, a character who Lois Lane falls in lust with. But Superman isn't invented because Jor-El ordered it, Superman is invented because without that persona, Clark Kent's life and those he cares about wouldn't be worth a plug nickel.
Sound familiar?
Clark Kent, Kansas farm boy turned reporter, would never do anything to hurt Lois Lane - she's one of the few people capable of keeping him on his toes, capable of really being competition. He's a good man. A good HUman.
Kal-El (the pre-1986 Kryptonian) may be fond of Lois, but she certainly isn't his equal in his eyes. The term 'Superman's Girl Friend' is only in her mind. And that Clark Kent spent a lot of time congratulating himself on how clever he was in fooling the hairless chimps.
Donner and the Salkinds made Superman the Movie a romance to make it more palatable to film audiences. But the Superman they were stuck with was Kal-El the proud Kryptonian, who, if taken to the logical extreme, was perfectly capable of noblesse oblige. He was a jerk.
Singer inherited him and tried to force him a little closer to later versions. But action-adventure cinema doesn't allow for that type of evolution to take place easily. It's not something that can be shown through special effects - Kal-El finally recognizing that Superman is a fiction and Clark Kent is the real person.
