He's a jerk, a two-timer, a double-crosser. He deserves everything you throw at him, your cutting remarks, your sarcasm, your enmity.
You're totally justified in spending a lot of time and energy in evening the score. You are the avenger.
The thing is, it's not clear that we benefit from carrying around all that vitriol. All the time we spend hating is time that we've given away to someone who hasn't earned our time. It's time we're being controlled by someone we don't like or respect very much.
Teaching someone a lesson is often overrated. Doing the lesson teaching in your head helps no one.
What happens if we walk away and make something magical instead?
You deserve it.