Should I Stay or Should I Go?

Wow, I really feel for you. No one can tell you what to do, only you know in your heart what you need to do. I can tell you from experience that you shouldn't consider how many years you are "throwing away" when deciding on whether you should stay. You sound unhappy and so does he. Maybe you could both use a break. All I can say is that if it is meant to be it will be.