But to me, this feels like incredible cake eating. What would be her incentive to end the affair if she gets all of the benefits of the marriage still?
Im not necessarily saying that divorce is the best way to end the affair. And Im certainly not suggesting that you need to give up and move on. But, in my opinion, allowing her to come and go as she pleases in your marital home while just spending nights with OM doesnt seem like a bad deal for her. What are your boundaries? Why does she get to spend every night out of the house while you act as her babysitter?
Again, this is just my opinion, but it feels like you are placing yourself as her Plan B. If the affair fizzles out, then youll wait around and pick up the scraps. Again, I dont see any reason for her to choose Plan B if it's always there.