Sir, you are NOT a weak Man.  You are a grieving Father who has lost his child and you have every right to be devastated.  My husband was also in the forces and like yourself, he did not think that anything could ever 'get' to him, but when I was diagnosed with cancer 6 years ago, and am now terminal, he freely admits that it has brought him to his knees like nothing else ever has.  Please do not hold your grief in..........why not tell your wife exactly how you feel?  This is something that you should go through together, not separately.  Please don't feel ashamed of your perfectly natural emotions..........there is no amount of training in the world that can EVER prepare you for the kind of loss that you have suffered......you have lost your child.......your baby boy.........you are not a block of ice or a piece of cold and hard stone......you are HUMAN BEING and your grief for your Son is absolutely normal.  I wish that there were some words of comfort that I could give you, but the only thing I can do is to offer my deepest and sincere condolences to you and your family, I truly feel for you.  

That is very normal behaviour. Would you think your wife or daughter-in-law weak if they fell to pieces when on their own or if they could not stop crying? I am sure you wouldn't. So give yourself the same grace. Losing a child is a terrible tragedy. It's not weak at all to grieve.

Let me tell you, it is absolutely normal behaviour and it takes only a real man to cry due to the loss of their loved one. I lost my wonderful life partner and soul mate of almost 20 years. I cry when I am with close friends of ours, I cry on my own...I cry when I chat online to my mother....Nobody ever trains you to be prepared for the possibility of losing a loved one....