Going dark might be OK but don't do it if it is going to seem like a punitive action.
Ask yourself this question about every move you make, "Will this get me closer to my goal or will it move further from my goal?" The goal I assume is to save your marriage.
You are still not sunk. She wouldn't be telling you she cared if she didn't. I am not sold on the EA either. Even if there is an EA, it is a symptom. Looking at your post a few above, she is more or less telling you what is/was missing and why she is acting the way she is. Almost like a cry for help.
My $.02
I would get Rob and a few others to look and share some opinions.
Me 44 She 46 S13 D9 M18 T23 3 years DB'ing Successfully busted