Don't send the email. Stop saying what you're going to do and just do it. I think you've been given this advice over and over and over again and just don't want to follow through.
Stop worrying about the level of your W's relationship with OM. Whats important is that shes not committing to the right steps to reconcile with you. Anything else is 100% irrelevant.
Stop confronting her. It only makes her pissed off and resentful and she reacts by saying '[censored] it, im done anyway' (my wife did the same thing, btw).
Stop thinking about what you want from this relationship and start thinking about other ways you want to define your life - your marriage isn't the only defining characteristic of your existence.
Drop the expectations - gives wife time to decide, your birthday, lease situation, etc.
I wish I could say more to you man but our situations are extremely similar in length, in process and in current status (only difference - which is a big one - is that I don't have kids). All of the above worked for me, not to win her back but to arrive at a place of relative peace and begin to see a real future without my marriage.
Me:38 W:39 No Children BD: 5/13 EA/PA Confirmed: 7/13 W Moved out 12/13