Man oh man.. I just got done working on the exact same thing.. the discovery of the cheating. I am so done with X...
Make sure you get all the blood tests to verify you are healthy and he did not give you anything from those other women. I have been negative once. I get to do this again in June.
Focus on staying healthy and being nice to yourself. This discovery is very difficult. It rocks one's self esteem. You are going to be angry.. maybe angrier than you ever were before in your life.
You did nothing wrong. Be glad you know so you can get tested and you can take care of YOU.