I agree with
>>3There is no way you could predict that happening. Don't blame yourself for the impossible. Live with him in your memory and never forget him. That's the best thing you can do.
At least he's at peace now. Don't make his death be the bane or your existence, live for him if not for you.
Be strong :) and also look after his fiancé, don't let her forget: life is a pain but the world isn't horrible so live for him if not for yourself