I also don't like the idea that Lois can only really forgive Clark for pretending to be two people if he can convince her that he had always intended to tell her. This theme crops up in a lot of fanfiction, and it makes me cringe. In both cases she just needs to accept that he had good reasons for keeping his identity a secret from everyone, and rather than having to come up with excuses why he didn't tell her, he would need specific reasons why he should tell her at all.
I have to agree with that. Clark needs to have a compelling reason to tell Lois, so he should not have to justify his not telling her.
That said, I will go with the view that Clark has no justified reason to propose before telling her. He would have told her if it had not been for Mazik's call at the start of the episode, so his actions at the end make no sense. Plus in Whine, Whine, Whine Lois rejects Superman and Dan Scardino, and choses Clark. She has shown that she choses the real man over the Superman, even when the real man runs out on dates without any explanation, repeatedly (sometimes in cases where even if he had explained, she would probably still be "Clark, why is stopping vandals more important than talking with me").
However I would actually go so far as to argue that really, Lois made her choice not in "Whine, Whine, Whine" but in "That Old Gang of Mine", where she so quickly embraces Clark on his return, while being non-plussed about seeing Clark. Even without hearing Lois's confession of her feelings, Clark should have realized that Lois loves and trusts him, and should have told her. From a story telling standpoint and the fun of the irony of Lois not knowing that Clark loves her, and has really good reasons to run off (except for a few times when he really doesn't, but I will grant Clark had a good reason to run off to save the musician, even if it just created more problems for both SM and CK), but I can see Clark needing to apologize to Lois for not telling her. I will accept that "Ides of Metropolis" would have been too soon for Clark to tell Lois, although it does add to the irony of his arguing for complete honesty.
On the whole I am glad the avoided this whole issue in "Man of Steel". I just love that they did it. We have seen every possible "Clark fools Lois into thinging he is not Super" story line done multiple times, and while "Lois helps Clark make/keep his secret" has been done some, it is a much more workable solution.
Anyway, while glasses and other misdirection may work with everyone else, it never was convincing for Lois and Clark. I mean she has seen Clark in just a towel and how he eats even before Superman debuts. At some point she should have clued into the facts.
