It was the wealthy and ambitious who committed suicide in 1929, not the poor. The college graduate who always wanted and expected to become a doctor is more crushed by rejection letters from Medical School than the graduate who rather expected the rejections. As Frijda observes, the human mind was apparently not made for happiness, but for survival. But anger, grief, insecurity, and jealousy are automatic, sometimes even unstoppable. The desire to remove serious emotional hurts from our life can become so primary that our strong feelings over-ride reason, close our minds to other viewpoints, and dominate our actions .
Suicide is a way to escape pain and hurts.
Likewise, the enraged ex-spouse can hardly think of anything else, certainly not any explanations for the former spouse's wrongdoings. The badness of the ex-spouse becomes an obsession, an unshakeable conviction which will often last forever, regardless of other peoples' opinions. Fortunately, under favorable conditions, reason can help us see other possibilities, see the likely long-term consequences of an action, see the implications of a code of ethics, etc. The more you know about those laws, the better your chances of controlling your unwanted emotions. The range of emotions is extensive.