I agree with Trimeresurus, you must have your doubts already or you wouldn't ask.
My other half has been to Iraq for 3 months and we survived fine, we wrote, spoke on the phone and emailed each other. He left to go to Afghanistan for 3 months today and the thought of us not surviving has not crossed my mind once. Instead there was tears because we won't see each other for 3 months and I keep thinking of the joy and relief when he returns.
You need to look at your relationship, there must be a reason you are asking this and doubting it will not work. Germany isn't very far away, one or both of you can even fly over to see the other.