I'm thinking of getting back with my ex just to lead him on for 3 years and then ghost him
Why would you do that to your ex?
I just want to see what he'll do when I dumped him
It's wrong to lead him on just to dump him in the end. This may backfire and you may end up ruining a second chance with him.
Hey, fuck you dude, I'll do what I want, if the stupid can't get the fact that I'm only using him for my amusement then too bad for him.
You should spend your time healing from the traumas that have caused you to be so cold and calculated. This way you can avoid wasting your time leading an ex on just to get revenge.