You need to get her to commit to a decision before the start of flying training, or the stress could distract and thus kill you.
Saw this with the married guy on my flying training. After nearly killing himself at Valley, they had to have a trial separation. Fortunately this worked. She agreed to shut up, he took her back, he lived and they are still married.
Saw it with a guy who married the widow of another FJ pilot. After a while, he took himself off FJ.
Ask her she would feel if you were woken up by a war callout at 5am one morning. It happens. "Where are you going?" "Don't know, I've been told to grab my desert kit". And the answer to her next six questions = "Don't know" x6, plus "Bye, Love. Got to go". I've had that; it tests any relationship. Ask how she would feel when she gets a call from some phone in the middle of the desert, for you to tell her that you have to go direct from the war zone for special duties on the West Coast of the USA, and then direct to the Falklands for QRA - mate of mine had to make that call.