What is going on with people in relationships encounraging their partners to kill themselves?

So,
Another young woman (Korean) was just charged with sending her boyfriend here in the US(both foreign students at Boston) over 45K text messages in two months. Most of these messages were berating him and tens of thousands encouraged him to die. Of course she has run back home to South Korea to avoid jail but we will see. These cases are becoming more common. Why? Do two needy sick people just find each other? Why is this happening more often, cell phones?
And should we jail people for text harassment when the other party is willing?