As someone who has been touched by suicide by the recent death of my brother in law its very difficult to make any sense of their reasoning. Outwardly he seemed very happy and life was treating him well, six months after and there have still been no dark secrets to come forward.
We may never know what was going through his mind and quite possibly he may not have know either, someone who takes their own life could be considered as not of the right mind at the time of the event. As we know many things can trigger mental illness and many mentally ill people give the outward appearance of normality, we can only hope the same doesn't happen to ourselves.
The Irish (i believe) have a wonderful saying that i try and live by myself when things get really bad and that is "A fate worse than death is better than dying."