I wouldn't move out. If she's willing to do counseling and a NC letter, there might be a part of her that's willing to work on her marriage. However, she could be using counseling to reinforce her negative feelings towards you. She'll probably pick you apart and make you look like the villain during counseling. In regards to the NC letter, just be prepared that it guarantees nothing. She can always still cheat with the same guy or another guy.
M41 W39 D3 Open Marriage Request by W 6/15 BD 9/15 1st EA 10/15 2nd EA discovered: 1/16 I moved out: 1/16 2nd EA blew apart 2/16 PA 4/16 I've had enough, filing for D