I don't see myself suiciding, because I am far too stubborn :D

Good. :)

Is that fair, or is it cruel?

It's an interesting question, for sure, but I would argue a fair outcome can sometimes also be cruel. And also, supposing the individual goes on living for his loved ones, why should it be fair when so little of our love and our relationships (romantic but also familial) is?

I don't know whether it's fair or cruel. Maybe both, but it's also an act of love. He's surviving to spare his loved ones the pain of living through his suicide, which is often tremendous. If you love someone a great deal and your choice is between your suffering and theirs, the choice is obvious. And I know you know all that already.

Kids lose their parents in a war or car crash, what is the difference?

All the difference. Kids whose parents suicide are gonna spend every damn day asking why mummy or daddy chose to leave them, one in the two people who are supposed to be there and not make that choice made that choice. There's no choice in dying in war or a car crash, so I would say quite a lot of difference, indeed.