Like everyone said, she is already in the process. If you're not having sex now then wait till you marry her. It will be actually non existent instead of virtually non existent

Plus she's going to be gone for a year and you know you wont see her at all. There's no holding a relationship together solely over the phone. She also says she doesnt know what she's going to do after that meaning she's not committing to you at all. I'd say hit it one last time and get out. Start getting over her. In no time you'll be posting a thread "I met this hot chick. So glad I dumped whats her name"