I am in a deep fog. Do wives ever come back? Should they? Should we allow them to? What is my one true hope?
Yes, they do come back, there are lots of stories on these forums about it. I know, because I've been digging through them to give myself hope, and there are quite a few success stories. Unfortunately there are no guarantees, and not knowing is the hardest part of all. It's a game of endurance, the success stories are typically in a window of 3 months to a year. If MLC is involved it can take much longer. I think there would be many more success stories if spouses were willing to wait it out, but in this "gotta have it now" society it's easier for most people to abandon hope early on and go find someone else.
As for whether we should allow them to come back, that's a question I've struggled with as well. My wife has breached my trust 3 times now (twice through hidden financial problems and once by the unexpected BD) and I'm constantly asking myself that if we do reconcile, can I ever trust her again? I think I could, but we'd have to go through in-depth counseling to figure that one out.
Regarding your one true hope, how much hope you want to hold in your heart is up to you. If holding hope is just causing you harm (as it sounds like it is) then maybe you should accept that it's time to move on and totally detach. Often when a spouse finally does decide to let go and move on that is when the wayward spouse suddenly finds them attractive again. Not saying it would be the case with you, but we all eventually get to the point where we have to decide to let go for our own personal well-being.