People are suicidal only for a limited period of time. In the vast majority of cases, things get better with time. Usually something changed. Whether it's the person's view of the situation or the problem itself is resolved, something has to give. All kinds of people commit suicide, including people who are depressed due to biochemical factors that have nothing to do with love.
More adolescent suicides occur in the morning before school or around dinner time.
These are times when more people are around and it's more likely that someone will prevent them from killing themselves. Unfortunately, it doesn't always happen that way. As long as people are alive, there's a will to remain that way. There are usually ample warning signs as overwhelmed people ask directly or indirectly for help. This is not a given.