I'm so sorry. I'm not even married yet, so I don't know how it feels to lose your significant other, but my best friend (female) died about two years ago. That was quite shocking (she was 19 at that time, car accident).
There may or there may not be a reason for each death... but we should appreciate all of the good memories we have of our beloved ones as their legacy.
P.S.:Something really nice is when you get to dream of them
in fact, I dreamed of my best friend last night. There's something magical about dreaming with those who are no longer among us, but that still have a place in our hearts.