It doesn't matter how hard it is, the fact is that if you say you are in a committed relationship, that means that you will resist no matter how hard it is being apart. There is never an excuse to have any kind of sex or intimacy with another because you're apart. That's the test for whether someone is truly committed to you or not. If after 7 months she can't resist temptation to jump in bed with another guy just because she is far from you, I'd start questioning whether or not she's the one for you.

I don't think it's a bad thing to give someone another chance but she needs to prove to you that she is committed to you and only you. You need to stick to your plan to break it off if she does it again, no ifs, ands or buts about it. She does it again, and I'm sure it will continue.

This just blows me away. I'm sorry for the pain she's causing you. I don't think it's right at all.

Personally my impulse is to say find someone that's actually going to be committed, loyal and faithful to you.