Lets go back to the issue of children and family. That's a big one. If you want children and your spouse doesn't that is a very big deal. Marriages break up over that sort of thing. Three years is a long time, but do you really want to invest even more than that only to end up hurt and unfulfilled? Didn't think so. Plus, you have to think about the fact that immigration to just about anywhere is like pulling teeth. I'm sure you have already looked into this and are well aware of the hurdles that you face in that department.
I think you are perfectly entitled to "date" this new woman without notifying your overseas girlfriend and find out who you like better. It may seem unfair to some, but hey, no harm no foul and this is what you want anyway. If it wasn't, you would not have mentioned the overseas gf dating other men.
It must be brutal (and expensive) traveling to another country every couple of months for three years. Time to cut the stress and find some love closer to home. That's my opinion anyway. Don't feel like you are throwing time away. You earned experience and so many times long-distance relationships just really do not work. It's not your fault, it just happens.
There are very few personal problems that cannot be solved with a suitable application of high explosives.