First, I am sorry that you are here Dolphin. This is a very tough place to be and we all know it.
How much evidence to you have? Is it solid. Can you forgive him? Think about what you want before you do anything. Wait for some of the pros before you do anything. Puppy, Coach, R2C. I am still too new to offer much good advice.
Tell us more about your relationship and your family. How long married? Ages? Kids? Give us some background and just sit tight for tonight.
Do you have the Divorce Remedy Book? Puppy Dog Tails always recommends other books for infidelity.