Have you ever been in love?
When you are suddenly cut off from something that you have wrapped your life around, something that you though with some glimmer of faith would be with you until you grew old, and something you had made great plans with...to suddenly abandon you without even a second glance. That kind of pain is rather grim, and "you can't just get a new one" when it comes to love. Love is something that has to be painstakingly grown from a tiny little seed of interest. You have to work for it, you have to spend time and effort, and sacrifice much for it. And should it turn out to be wasted effort, wasted time, and wasted emotion...well...often times all that happiness, turns all at once into soul crushing, brooding, and deadly grief, and often times one loses the will to live.
Someone you love isn't a toy, you can't just replace them, or "get a new one" when you lose them. You have to start all over again, from the very bottom, and sometimes you just don't have the energy to redo your life, and you feel like ending it.
The only time you can ever readily "get a new one" is if you most likely didn't 'love' the girl in the first place and all you saw was a 'pretty face, and some hot pussy'. Which is a very vile way to see a girl indeed.
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Suicide is a two edged sword. It takes great bravery to terminate your own life. But it is also very cowardly, and sad, that someone could hit the bottom so hard, they don't want to exist, and any destiny they had is now gone, for something that time may some day heal.
Euthanasia of the terminally ill however, as long as the person is conscious enough to make the decision, and there is no hope. But don't pull a Terry and starve the person to death.