Let me add to the chorus of those saying you have nothing to be ashamed of and as to how much she actually new beforehand, i don't know you as a couple, so that dynamic is not something i can comment much on, but i will say this: A lot of guilt over non-disclosure is misplaced in my opinion. What you may feel after the fact this traumatic event could be that and what you really may be experiencing is self-awareness rising to the point of action.
Couples never sign up for the " I'll never change our entire marriage plan". It is unfathomable. Yep you are the same person you've always been her spouse but you change. We all do. Sometimes those changes pull us close, sometimes those changes pull us apart.
I personally think we give way to much emphasis on gender in much of society and in the totally wrong ways. If you use terms like hey i was a Marine what does it mean..(maybe...great, brave, leadership, traditionally masculine ventures) or Prince (very masculine term that sort of means, you are her champion and traditionally male place of honor etc). I call my boyfriend my prince all the time and i know what i am trying to communicate there.
i think we sometimes show our own bias and in that way our loved ones can pick pick up on it. The truth is that those terms above are largely BOTH feminine and masculine. You are still her brave soldier and her champion. Your disclosure and desires change none of that.
It is scary to face such pain and potential loss about someone we love. Therapy will be invaluable to the future of your relationship so i also encourage you both to go there. Whatever happens though, you are you and our loved ones need to love us not according to our role, not according to the idea or image of us, but us as people. That doesn't mean her hands or tied or she is trapped in any way, but love means we choose to figure it all out in the kindest way possible for both people.