In truth a cheater harms themselves more than they harm you.
My wife cheated on me just before we got married and when she told me that she expected me to hit the roof, little did she know I already knew.
Afterwards she asked me why I wasn't upset at all.
I replied, the lack of your moral fiber, integrity, honesty and self worth has no reflection of my own my own integrity and self value.
I am happy because I deserve a person better than you, it's you that should be sad and disappointed and angry not me.
People will cheat, this is a given there's no use dwelling on the fact. It's much better to concentrate your efforts developing yourself into a high value human being.
If your partner cheats on you, and you have a true moral compass and have accumulated a high degree of self value. you will undoubtedly have no problem finding someone else if the infidelity bothers you so much.
The best way to get revenge on a treating spouse is not make a big deal out of it.