Catherine numero uno was the (second) wife of Peter the Great. She didnt killed her husband. Catherine numero dos was the wife of the not-so-great grandson of Peter the Great. She killed and ate her husband, later said to Nikita Panin, the tutor of the heir, 'the future generations will never forgive me.' She was a maneater.
While I am aware that as a result of Peter III's death while in custody, she reportedly said ‘
My glory is spoilt, posterity will never forgive me’ as translated by Simon Sebag Montefiore in his
Catherine the Great and Potemkin, your post is the first time I have seen any mention of cannibalism. She didn't actually kill him herself either as she wasn't at Rapsha and was informed of the event in a letter from Alexei Orlov, who was in charge of him there. The fact that Orlov asked for her forgiveness would indicate she didn't plan his murder at that point, although she might have intended that he wouldn't be around in the long term.
When exactly was she supposed to have eaten him? Did she stand with a knife and fork beside the open coffin while he was lying in state at the Alexander Nevskii Monastery, helping herself to a slice every now and then? Or after he had been interred there, did she have him dug up in the dead of night and have him barbequed? Or was it fricasseed?