Hi Muddle,
Just got caught up with your new thread. While I think your letter was very eloquently written and heartfelt I do not think that you should send it. For one is will piss your W off and two you want the A to end because your W wanted it to. If OM breaks it off with her because of the letter your W will resent you even more.

I also think that a separation talk might be a good idea. She needs to fully understand everything that she is about to lose. What does OM have to lose? Is he M? Does he have kids?

Hang in there buddy!