You're being totally reasonable, she's being unreasonable. It takes a strong person and relationship to deal with the stresses and difficulties of military life, especially those involving combat roles.
Lots of people just don't understand how the military is, and that causes problems. In the long run she'll have to choose whether to accept it or to move on, because it doesn't get much easier.
Special Forces have the highest divorce rates.
Coincidence, I think not. Marines and Navy are probably a close 2nd.
All you can really do is try to explain to her. If she doesn't believe you, then she either doesn't trust you or just probably won't ever understand. Many civilians can't understand for various reasons, the concepts of the military are beyond their comprehension.
Best of luck.
b