I'm going to ruin my cheating ex's chances with other guys
Why would you go out of your way to ruin their future chances with other guys?
Because she's a fucking asshole.
Being resentful because she cheated on you is understandable but that doesn't mean you should try to ruin her future chances at a relationship. You should just move on and do your best to be a better person. Make them realize leaving you was a mistake as their punishment rather than messing with their future.
What if I raped her for revenge?
You should drop this immediately and move on with your life. It is crazy to think raping someone would be justified as a form of punishment. If you can't get over your feelings I think you should talk with a therapist.