But... i suppose it depends on the person.
ANSWER:
The only way you can do is ignore him, that's the reason why he became ex, don't you agree?
The best way to prevent revenge from an ex girlfriend is to have an amicable break up. Do not bad mouth the ex, do not make her look bad in front of her friends.
"Sucess is the best form of revenge."
Taking revenge is not an appropriate solution. You both can talk and sort out the problems you had.
Make a list of all the good things about not being with your ex. Make it as long as you wish. Make yourself the priority. You are more important than revenge against your ex or your ex himself. Think about what makes you feel good and do it, whether that is a hobby, hanging out with friends, etc. Do activities that you enjoy doing without him.
If they are your ex move forward, don't look back - they are just not worth it. Revenge is for the weak - you are a stronger person by just walking away.
Honestly this is just childish, I don't care if she even has cheated on you, revenge is for little boys. Karma will be a bigger kick in the butt then you can ever be, it is inevitable. Only time will tell you and show you that revenge will only make you look weak, and actually psycho.
Ignore them
You dont. If you do, you will just be as bad as him. *The other poster is correct. Revenge is the most useless thing one can do and depletes one of energy. Even if you should get revenge you won't feel as good about it as you think you will and you'll just be at the bottom of the same barrel he is in.
if your a girl then go to her EX that will make her really mad if your a boy then dont get revenge then you will look like a jerk.
Pollulate, Pollulating. To fester with pollution, implies a nasty chemical reaction or toxic, poisonous things... Karen's brain is pollulating with thoughts of revenge against her ex husband.
Forget him and get on with your life. The best revenge is to live well. Or her.
Hitler.