I was thinking about you on the way to the store after I posted. The other experts may offer some light, but I have what some could say is an odd feeling about your stitch. I feel it is safe to assume that the OW has at least some impact on your situation, but there has been no confirmed affairs either P or E. Let's assume, because I feel safe in this one, that there is a EA going on. What I find confusing is your stich's time line. It seems to be going awfully fast from what I have read on this board and witnessed in real life. It seems to me that even in instances were both parties want out, that divorces take around six months to process and get everything done to the point to actually go in front of the judge. In your stich it is more like two months and that seems incredibly fast. Now it may be not the long because I am only basing my opinion on what I have seen, but I have a theory. Could your wife actually be sustaining from a PA because she is married (or the OW)? It sounds crazy, but could that really be what is driving the speediness of this? I would like some other opinions to help LS with this crazy notion.
Remember that even though your stich is different from regular DB, you will see the slight cracks that allow sunshine in. That is how it is all going to begin, because there is still a lot of work to be completed. I started out with a small talk like yours with the same outcome every two or three weeks. Then they became every other week, then once a week, then every other day (of course by this point the "we will never get back together again" talk had disappeared. You don't have that luxury since the legal proceedings are going so fast, but just focus on the end goal.
There is one other idea you will be faced with more than likely if your marriage is saved. It really isn't DB material, but it will come up. I suggest searching the net with a search term combining "Pandora's Box" and bisexuality. If you find something, which I think you will, you will understand.