Amos's reaction when he realizes that Roxie lied to him about murdering a burglar, that said "burglar" was a man they both knew well, and the only explanation is that his wife was cheating on him. He starts angrily ranting about how much of a "sap" he was.
Later when Roxie is acquitted, he was willing to forgive her and ready to start over as a family - only for her to bluntly tell him that there is no baby, leaving as Amos looks on with an utterly crushed expression.
Kitty in the film is still a murderess, but you can tell she was really hurt by her husband cheating on her and wants no part in the media circus that follows. Her response to a journalist asking if she knew the women she killed is a Death Glare and Groin Attack. It's more than likely that, unlike Roxie and Velma, she truly had a psychotic break and would rather go to jail than have Billy representing her.
