Need Support & Guidance

I've been NC text for 2 weeks, NC physical for 4 weeks. 4 weeks ago I contacted via Facebook another one of the OW. Today, she returned my message. I know this will come as no surprise to anyone.....BUT HE'S BEEN SLEEPING WITH HER THE WHOLE TIME!!! At the apartment I paid for!!! I don't even have to go detail into the rage I feel right now. I so want to break contact, text him and tell him I know he cheated on me. I want to feel that victory for 2 seconds....but then I KNOW what doors it will open and that is ultimately not in my best interest to spend the at least days if not weeks in the aftermath of his response.