If you agree with her developing a relationship with the OM you will very likely end up divorced. If she wants a business arrangement which you live as roommates than you might as well get divorced. At least you won't have to put up with your wife's nonsense and move on with your life. The point is the longer you put up with your wife's
craziness the more likely your marriage is going to crash and die. It is important to stand firm and not allow yourself to be part of her drama . The message that you will be delivering to your wife is that you are not going to be there supporting her while she sees if the relationship with the OM becomes serious enough so that she can dump you. Wishful thinking that suddenly she is going fall back in love with you, if you cooperate with going along with her affair, is not going to work. It will only make you feel more resentful and make her view you as a weak man. She has to see that you are not willing to accept a marriage that is a sham and that even though you love her you are not afraid to move on with or without her.