Re: All Things Superman: An Open Discussion - - - - - - - - - - - - - - - - -
As other have mentioned, having Lois just break up with her current fiance in favor of Superman during the events of MOS wouldn't make either of them look good, especially Lois, and would be totally reminiscent of the situation from SR.
Plus, considering on how much they have to tell, I wouldn't assume that they'd have time to introduce the backstory that she was or is currently engaged with someone.
And saying that she's a widow or a divorcee wouldn't be the best way to say that she's a "modern" woman.
Plus, it would just further tarnish the iconic relationship in ways that the New 52 hasn't already.