The idea Chuck would be that clueless was unconvincing -- especially given that he proposed to and married her when it was believed another of her bodies had been destroyed, meaning she'd have to leave the Legion. There's no way they wouldn't have discussed this topic long before. And saying "I never gave a moment's thought to how you must have felt" takes him off the "sympathetic reader-identification figure" side of the register and over to the "kind of a selfish dickwad" side.
It was obviously written this way for the sole purpose of providing a reason for Luornu to deliver all that exposition, plausible characterization be damned. Levitz got much better later on. (I think he also cut down on the "breeps" -- or did I just stop noticing them so much?)