Have a talk with him. Tell him you are starting over with him, and his behavior from that day on will be used by you to determine whether you will stay with him.
Tell him the rules. You will find great lists of ground rules/boundaries here on SI.
#1 No more A's
#2 No more secrets, about anything. That means, no more doing things to "protect" your feelings either. If he messes up he needs to fess up to you, not try to cover it up.
#3 End friendships with all people who knew about the A and didn't tell you. No sneaking to communicate or get together with them. He will balk. It is either them, or you. Period.
#4 You get access to all phones, computers, etc. and you can check them any time. Don't forget, you can also check the phone bill for all phone numbers dialed.
I'm glad he didn't go to the festival, but his sneaky move regarding the tickets is a red flag. Don't. Believe. A. Liar.