If you've just learned about the infidelity, you more than likely are feeling overwhelmed by emotion. You might want to scream, break things, be confrontational, or otherwise destructive. After all, it feels good to blow off some steam when we are hurting, right?
For your safety and the safety of others, it's probably best if you take some time alone and just breathe through what you are feeling. It's definitely easier said than done but once you give into anger, you could end up doing or saying some things that you will regret.
Pro tip: Water can feel really cleansing in a moment like this. Take a hot shower, cry as needed, and allow yourself a few moments to digest everything you have learned.