Huh... I don't know if the 7 deadly sins really fits. Like a lot of bad partners would embody multiple sins at different times. A dude who gambles all your money would be greed, pride, envy, and wrath at least.
Thought this before but if a story's talks about scum dudes a bunch then I kinda want the author to bring it in terms of depicting scumness? Either make me think yes, that is what real awful dudes are like or show me a character who could easily be the male lead of another story and point out why he's scum.