As you likely know, I think you have waited waaayyyy too long... And there always seems to be a special event that keeps you from revealing that "you know." You are protecting her from her consequences...
Do you think she will end up with OM? Is he willing to leave his wife for her? When my H confronted me he didn't tell me everything he knew or how he knew. He sent me a text from work one morning... It said, "Check your email." I thought it was weird. Normally we would talk on the phone every morning while he was at work. That morning I had called a few times but he wouldn't answer. That was odd. So I read the text and went to check my email on my desktop... There was an email from him with the subject line: I KNOW.
My heart dropped, and I was shaking... I read the first line and did a full-on freak out just like hoosjim's wife... Even though I didn't have details of what exactly he knew, I knew he knew...