One of the things I never understand in these threads is what am I (are we) supposed to be doing in this strange area where we're not actively separating or reconciling after D-day?
The mantra here is that you cannot control another person. You can only control you.
Another mantra here is that the over-arching goal is to get yourself (as the betrayed spouse) out of infidelity.
To be clear, as long as your WW remains an active partner with her AP in the business venture, she and therefore you is/are in infidelity. A commonly used metaphore is: find yourself a boat, point it away from infidelity, get in it and row as hard and as fast away from that place as you can. If she ever decides to quit participating in infidelity, she will figure out a way to swim out and catch up with you. If she doesn't do that, the marriage never had a chance.
To distill all of that to more practical advice, the process of reconciliation is a long play. It can take many years of 100%, both feet all the way in emotional investment by both partners to even figure out whether reconciliation has a chance of succeeding. The affair will forever be a plus one in your marriage. Reconciliation works when the partners learn to live with this constant presence and adjust their marriage to succeed even with this plus one.
At present, your WW has not taken even the first step toward the process of reconciliation (in fact, due to her choices, she will not be in a position to even consider that first step for a year or more). Therefore you have not even started this multi-year process.
Further, your WW's affair was deeply immersive and emotional, and she is behaving in profoundly entitled, avoidant ways now. All of these factors augur for the conclusion that reconciliation is unlikely to ever succeed in your case even if she were to invest in reconciliation. That's not to say you couldn't stiff upper lip it and stubbornly remain nominally married, but it's unlikely you will achieve an actual happy, functioning relationship with your WW given the facts here.
I'd suggest looking in the bathroom mirror and having a long conversation with your 60-year old self. Ask that guy whether he thinks you made a wise decision investing 5-10 years of sturm und drang into what is likely a futile effort toward reconciliation with an un-remorseful cheating wife who refuses to disengage with her affair partner.
On that last point, the "painted in a corner" thing, I really do think the binary options are (a) leave the business venture now and watch it flounder and fail, or (b) see it through for a chance of success. I've been around a lot of startups. The capital stack and investor network at this stage is a delicate crystalline structure, not at all cemented into place. Just the slightest puff of a breeze could cause the whole thing to collapse and shatter.
However, I would remind you that, end of the day, your WW chose this. She is a smart, capable, accomplished woman. She was fully able to foresee that this would be exactly the position she would find herself in when she decided to launch a sexual affair with her start-up founding partner. Therefore, it is rational to conclude this is precisely the outcome she wanted to force upon you.
I want you to consider that. She chose this place for you, without your consent. If you had a friend in this position, what would you advise him to do?
[This message edited by Butforthegrace at 2:31 PM, Friday, October 2nd]