My Story...possible "grass is greener" scenario?

[MarkG]

And we werent married, just engaged and living together...so I really have no power to say I wont live in any sort of open relationship. Essentially we are like a couple thats already divorced. So we are done pretty much unless the OM treats her so horribly that she wants to get away from him...and he does seem to be a predator with excellent conversation skills...so I'm probably out of luck.

You do still have the power to say you won't live in an open relationship. If the only reason she would come back is he treated her bad would those be conditions on which you'd accept her back? Also ask yourself are you saying you wouldn't accept her back after a physical relationship with someone else because you wouldn't because of values & boundaries or because you're hurt and angry. You may think you need answers right now but I guarantee you snap decisions will be the ones you will regret later.