Iris Murdoch said this quote
“ But jealousy is a dreadful thing, Jessica. It is the most natural to us of the really wicked passions and it goes deep and envenoms the soul. It must be resisted with every honest cunning and with the deliberate thinking of generous thoughts, however abstract and empty these may seem in comparison with that wicked strength... There is no merit, Jessica, in a faithfulness which is poison to you and captivity to him. ”