"Deceit" is such a negitive word.I think Clark's sins were ones of assumption and procrastination.He believed his love for her allowed them to share their grief. The sex thing was spontaneous.That he was slow to reveal his secret was a mistake in judgment that later came back to hunt him.
I think Lois was deceived and betrayed by her own emotions.She says she gave Clark/Superman every thing she was. That was not supposed to happen.Now she has no idea what to do with her self.