The past is the past. There is zero justification in stepping out on your marriage. If she was unhappy and didnt think she could move past your poor choices in the past, she should have just left and filed for D. You cannot change the past. You can however forge the future.
Stop talking to everyone about it. The A is out in the open now. Just keep quiet about it. Nothing changes, you still need to focus on yourself. Thats it. Stop focusing on W, stop worrying about what everyone else is doing or thinking. Walk your path, dust your shoulder off and move forward.
If your WW wants to work it out she needs to show you. Words mean nothing. Actions mean everything. Again my Ex WW cheated with her boss. In the small window where I would have maybe reconciled, my EXWW would have had to quit her job. She would have had to choose me and our family over OM and her job. There wasn't a chance in h3ll that she was going to do that. So I quickly dropped any hope that R would happen at all.
She can't focus on you and your MR if she is seeing OM or talking to him at all. She would have to completely remove herself from any sort of interaction. Thats not for you to tell her though. You can't give her an instruction manual on how to repair your MR.
M:16 T:21 H(me) 38 WW: 38 S11 D16 D19 Red Flags of A: March 2018 ILYBNILWY: August 4, 2018 Moved out of MBR: September 24, 2018 BD/Confirmation of A: October 31, 2018 D Filed: March 27, 2019