Meh.
Mis, you need to tell her to snap the f**k out of it or f**k off.
Quite simple really.
Forget about all this "I owe her" and "she needs me" bullshit. If the two of you are miserable then just break it off. It won't improve over time, in fact, it'll just get worse. It's obvious she isn't the one and what happens if somehow, you put a bun in her oven? That would be a friggin catastrophe. If you break it off, she'll go back to the states and resume her old life and probably be happy as a pig in shit in six months time. You can resume trying to bang half of the female Asian population and you'll be just as happy as well.
It's plainly obvious to me, what you need to do. Man up and get it overwith. I expect to hear that you've broken it off by this time tomorrow.
Love should not be difficult. It should be the easiest thing in the world.