Maybe a different perspective - coming from a guy whose wife had a 3 year LTA and we are now, 6+ years later, fully reconciled. How does that happen?
A few things to consider that might be of help to you:
1. It takes a lot of time and a lot of pain. We all want it to go away quickly but the reality is that, 6 years later, I think about her affair every single day. So it will take a lot of patience and solid temperament if you want to make it work. Are you up for that? Is she? Only you can answer that question.
2. For many, the A is simply a deal-breaker. Some recognize this very early on, some go several years and then recognize that they just can't get past it. Or their wife doesn't have it in her to do the hard work. My suggestion would be to consider these possibilities NOW. Going through the motions for a few years only to be exactly where you are now is pointless. I know that you love her. But look objectively - is she someone who has the capacity for the kind of work you require?
3. How do you deal with the Plan A, B, C thing? Simple. You need to recognize the affair for what it is - an escape from a life that may have gotten a bit hum drum and the fantasy provided the excitement. Think about it - the very notion of how "in love" they are is total bullshit. Does your wife know that he's actually a pig? That he pays his bills late? That he gets all pissy if he doesn't get laid on Saturday night?
Of course not. She only saw him when he was at his best (and, certainly, when he knew he was going to get some, right? Shocking that he would be that nice to her THEN!). The same was true the other way around. He didn't get to see your wife when she was pushing out your kids, sick with the flu, or when she was a nasty SOB because she was on her period.
The point is, when you really stop and think about it, affairs are nothing more than fantasy. The "I love you's" and the "Let's run away together" are rooted in nothing more than bullshit. And if you don't believe me, have you ever wondered why so many of the "Let's run away togethers" quickly turn into, "Maybe we'll just keep things as they are." Why? Because the guy's getting laid (what he wants) and, in the end, your wife still has you and her family (which is really what she wants). The "Let's run away" together would take the shine off the bullshit they're spewing.
See the affair for what it is - a reflection of your wife's shitty coping skills. Nothing more, nothing less.
4. Does your wife have it in her to be TRULY remorseful? And by that I mean someone who doesn't just realize that she made a horrible choice and wants to "win you back." It's someone who recognizes that it's all on her - and ANYTHING that needs to be done she will do. THAT is a very hard role for people to take on. Most people who have affairs are not simultaneously doing research on how to heal their husband, or how to be a better person. So when the affair is suddenly discovered, most people SAY they're going to do "whatever it takes" but, in reality, they have NO IDEA just how much pain they've inflicted and how LONG it will take.
Lastly, it has taken us 6+ years to really get to a place where things are good. And I mean, REALLY good. There was a long time when I didn't think we'd make it. And there are a LOT of marriages that don't - far more than ones that just sit in this awful purgatory. Be prepared for a very long ride. You will think about this incessantly for a long time. Hang in there and get the help that you need.
Infidelity is a horrible pill to swallow. It's a lot to ask of a guy to reconcile - and just as much for his wife to overcome. It CAN be done but it's definitely not for the faint of heart.
Good luck. PM me if you need.