Second track from the Chicago soundtrack, released in 2002. Performed by Roxie Hart (Renée Zellweger) in the middle of her approach to the police after she shot Fred Casely, while her husband, Amos, is taking the blame for her. She starts singing about how kind he is and then becomes furious when he connects the dots, figuring out that she had been unfaithful to him, and turns her in to the police.
Check out the original performance here:
https://www.youtube.com/watch?v=_C0_gY75zUU