Life isn't like math; there isn't a right solution that applies every time. There are many factors to continue, not the least of which is whether you can ever put it behind you. About the only thing that you can hang a hat on it to not rush to decide. The only way you can hope to get some perspective on the situation is to wait. I'm talking like at least a year. And if you don't think you can wait that long then you definitely need to cut her loose.