If you caught your boyfriend cheating with a married woman would you inform her husband?

Yes... Wouldnt you want to know if you were her?

Nope, simply erase that person from your life. You are much better than stooping to that level of revenge for what? Karma will come back around, let it happen without you getting revenge. Be angry, upset and whatever else you want at your own boyfriend(which I hope he is your EX boyfriend at this point) and let it roll

Dump the dude, and move on, and leave his business alone. Your doing it for revenge.