I know that the DB coach has given you some advice and you've done that and if you want to stick to that plan, i pray it works for you, but here's a slightly different perspective...
The sits leading up to this are far diff than yours, but:
I had an EA (online) that lasted about 3 months. My husband did the same as you and found the emails. We shared pictures and sexual fantasies. I told him i loved him (i didn't, but he made me feel good) anyways. My H found the emails, he confronted me immediately. He made me sit down with him in front of the computer and go through a ton of emails and pictures and stories. I have never felt so ashamed of myself. He also said this. "I love you and I want to stay married to you. You have 2 choices. You either stop talking to him here and now or it's over" I deleted the email account while he watched and the next morning I changed my cell phone number. I haven't spoken a work to him since. Quite honestly i don't miss the EA or OM. I only think about it when H asks about it. Did that fix everything, no, but now we can.
Only you know your W, but i would highly recommend telling her she needs to make a decision. You or him cause you will not stand for this. Even if it is only flirting and talking. you deserve to be treated better than that.
all my best... ann
If i can't fall in love... I'd like to fall in chocolate! ~ Author Unknown