What did you do to get revenge on your significant other for cheating?
Closest I ever got to this was a bf in high school who cheated on me. Bought a doubles ticket to a school dance and never showed up, leaving me alone and crying and calling him repeatedly wondering what was up. I always arrived at school early because of my mom so while I was heading to my locker the next Monday I found him making out with another girl. Turns out he'd spent dance night sleeping with her and turned his phone off so I wouldn't bug him.
I confronted him about this in front of her, hoping at best to make him look like a jerk in front of the girl he was cheating on me with. Instead she was horrified as well, kicked him right in the family jewels, and made it up to me by taking me to breakfast across the street before school started. She apologized and said he didn't tell her, and if she'd known she never would have let him spend the night on the dance night.
My thought of 'revenge' by revealing him as a cheater earned me a friend for the remainder of my high school years and she was a cheerleader so she pretty much made sure none of the others ever went anywhere near him again and honestly half the girls in the school just gave him the stink eye for the rest of the year when it got around what he'd done to me. Worked out quite nicely.