Well, I vote for Plan B. I think that more than anything you need a break from this. And if you think you can hold out awhile longer, I would take that route.
I do disagree that exposure had no effect. I believe it had a great effect in your case. It was one of the only times your W had to face consequences of her actions. She was royally pissed off, too, if I remember right. Even though her creepy family doesn't care [I remember that her mother actually even aided her last affair, didn't she?] I would still get her current affair out there and talk about her "adultery" openly.
I would most especially tell your boys, and I will tell you why. Being seperated, she is bound to introduce them to her paramour du jour. She will teach them that adultery is perfectly acceptable and they will grow up morally confused and turn into little adulterers themselves. I know how horrible this is from personal experience.
Kids instinctively know right from wrong and when that is not validated - or even contradicted by adults, they begin to doubt themselves. It is much easier to believe that oneself is stupid than to believe your own parent is actually ammoral. If they are going to be around her and your goofy inlaws, they desperately need your moral guidance about this since they will never get it from that side.
And most importantly, your wife is going to be in for a rude wake up when you aren't around to take care of her. You are probably meeting 3-4 of her needs and she has been taking that for granted for years. She is of an age, that unless she is a smoking hottie, she is not apt to find men as anxious to take care of her as you have. Being "single" she will be competing with 29 yr olds - with no baggage. So her little fantasies about other guys will quickly crumble when the light of reality shines in.
When I confronted my W about the new guy, she was just angry that I was snooping again... so was her sister. How could I possibly break her trust in this way and invade her privacy??? LOL Snooping is not below my integrity if it is to protect my family.
<img src="/ubbt/images/graemlins/rolleyes.gif" alt="" /> I agree with your reasoning about snooping. Once you go into Plan B, I would shut that all down so you can withdraw from her mess. And I do believe that snooping is a VIRTUE when one has cause. There is nothing dishonest about snooping. You have a right to know every single thing your wife does.
Lastly, I suspect that your wife will go ballistic when you go into plan B because she does not want to lose control of you. I envision her using every trick in the book to get you back on the massahs plantation. I think she is really very dependent on you and doesn't want to lose your services.
Therefore, i would only do this if you fully intend on going black as night and are willing to withstand her onslaught. Because if you let her in even a little tiny bit, she will have won. She will have spit on your credibility and proven that she can manage you at her will. That is a dreadful, dangerous message to send a selfish, entitled wayward because it is a forfeiture of any leverage and any credibility.