How to get revenge for having been treated like shit/ cheated on?

*Spare yourself the time to write revenge is not a good thing, I don’t give a shit and I also don’t give a shit if you say I should move on, I won’t be happy until i made him pay for it.*

When my ex moved back to his hometown for work things got a bit difficult because of distance and of a friend of his hitting on him the whole time.

She had a crush on him since forever, and she insisted and worked her way until she got him to sleep with her.

she's Not good looking and quite unkempt and he had never really considered her because of that. She’s rather unattractive and pretty much a summation of all the traits he used to call “hideous” about girls (crooked teeth, fatty, cross eyed, horse smile, frizzy hair...)

After we we broke up he kept sleeping with her and at a certain point she turned into his girlfriend. Guess she obtained what she wanted.

I just want to make him pay for it, or both of them since she is the one who insisted with him even if she knew he had a girlfriend.

I know that his soft spot is her being ugly, he’s extremely touchy about that, probably he’s internally pissed off that he ended up with such a troll, she’s the ugliest of all of his friends girlfriends, and by far. Plus he’s very competitive in these things. He used to brag a lot about me being the prettiest out of all of his guy friends girlfriends.

Ideas on what to do?
How to get revenge for having been treated like shit/ cheated on?
Add Opinion