Face it head on.
Cheating can be a difficult thing to confront your partner with. After all, you want to trust them. If you suspect your partner of cheating, you have to confront them honestly and directly. You will only be able to move on from the issue of cheating once you've determined the level of unfaithfulness your partner has committed.
Don't try to "get back" at your partner by embarrassing them or cheating, or having an emotional affair.
You have every right to be angry and hurt, but doing something to retaliate for your partner's infidelity will not help you feel any better in the long run. Don't commit an act you'll one day regret.