Jealousy in moderation is normal. It shows that we care about the other person. a spouse or partner. Morbid jealousy is pathological. It is an irrational emotion that signals a psychopathological disorder, write forensicpsychiatrists Michael Kingham and Harvey Gordon in a 2004 issue of Advances in Psychiatric Treatment. Morbid jealousy is signaled by irrational, obsessive thoughts centered around a lover or ex-lover’s possible sexual unfaithfulness, together with unacceptable or extreme behavior. Surprisingly, it occurs more often in older individuals and in males. The average age at onset is 38 years. The authors emphasize that morbid jealousy is a symptom, not a diagnosis.