Background*: The people of the delta region of Nigeria are generally migrant fishermen who migrated from Sierra Leone and Gabon. These people are used to water in a way, so much so that it is commonly said that wherever there is a river someone from the Delta region is not far. These fishermen practice two forms of marriages: a big dowry marriage (wherein tradition demands that the groom offers much payment to the wife’s family) and a small-dowry marriage, (in which much money is not paid by the groom but succession is matrilineal). The small dowry marriages are the most frequent. The populace venerate their ancestors and belief in the water spirit, Owuamapu part of their pantheon. Further, they practice divinations to interrogate the causes of death, and also perform rites that initiate members of different communities that are inserted in certain practices.   

Sources: 

A brief walk into the lives of one of the world's most ancient people, pulse.ng (accessed: April 23, 2019).

Abi Alabo Derefaka, Archaeology and Culture History in the Central Niger Delta, Onyoma Research Publications, 2006, preview at africanbookscollective.com (accessed: April 23, 2019).

The original version of this myth appears in Egbe Ifie's Marriage with Gods and Goddesses: In Classical and African Myths published by End-time Publishing House Ltd, Ibadan, 1999: pp. 35–37. This is a summary of the myth. The full text can be read in the book cited above.

Aziza was born with physical grace. His handsomeness was praised in songs and hymns all over the countryside. This made him grow up with the certitude that he had extraordinary assets. He became proud and lazy. When he got married, the young man was an empty vessel. He did not have much to offer except hypothetic beds of roses. 

Aziza and his wife had two children who unluckily passed away because their parents could not take proper care of them. The wife could not bear this so she left her husband. Having lost everything, Aziza started wandering lonely like a dog. Deep in his depression, drunkenness welcomed him. He drank heavily in order to forget his sorrows.

One night, after a crazy party, Aziza staggered home. There, he met a stranger lying on his bed whom he mistook for his wife. He was about to light the room when his visitor stopped him. The man listened carefully to the voice which he couldn’t identify. “Who are you?” he asked. The bewitching voice instead invited him to be a man. Being half-conscious, he thought this was god-sent. And what happened, happened! He submitted and slept with her.

The next morning, Aziza did not wake up early, having spent a sleepless night. When he woke up, he discovered that his one-night bed-mate had vanished. He turned his house over but she was nowhere to be found. The following evening, he waited impatiently for this stranger till late night but she did not show up. Disappointed, he went back to his old habits. The next night, after Aziza had taken enough alcoholic liquor, the woman appeared unexpectedly in the middle of the night. This time, she revealed her identity to Aziza that she was a mermaid and promised she would make him wealthy under a few conditions. They agreed that Aziza would never look at her face, never reveal their relationship and never disclose the source of his wealth. The covenant set, the mammy-water prepared him for an underwater trip. Since the young man could not swim well, she used a magic wand to prevent him from drowning. At midnight, Aziza held the woman’s long golden hair firmly as they embarked on a two-week journey.

On his return to the village, Aziza became prosperous. In a short period of time, he built a castle for himself. All his brothers were suspicious of him. The newly-enriched man lived a happy life regardless of the gossips. He married a beautiful young girl called Ehre with whom he unfortunately did not have any child after several years. Together, they went to a soothsayer who revealed to them the downside of Aziza’s wealth. “The mermaid has given you riches in exchange for your virility”, the mystic revealed. Both spouses were saddened by this news. Back home, Ehre asked to go to her parents in the hope of taking in the sad situation. Aziza did not like the idea, all the more because he had to pay her regular visits. This disagreement resulted in a quarrel during which Ehre revealed Aziza’s secret. The man tried to save his face by denying his wife. But it was too late. His secret was already out and the mermaid was mad at him. The latter backed out taking away all she had given Aziza who became the miserable man he had always been.

Marriages and other intimate relationships between water spirits and human beings, in most communities in Nigeria and Africa, are often sealed by a covenant. Since the former do not always want to fully reveal their identity to the ordinary man in the society, the covenant becomes what makes the relation secret. Both parties reap fruits from these relationships only when the terms of the covenant are respected. When the terms of the covenant are broken, the result is usually desertion and suffering, especially from the inferior party. In Elechi Amadi’s The Concubine, for example, the protagonist, Ihuoma, pays the price for breaking a covenant as she attempts, in collaboration with her human intended spouse, to break the covenant between her and the sea God, her spiritual husband. Her human attempt to desert the Sea God results to the death of Ekweme (her human fiancé). This death brings untold suffering to her, as she sees herself as the cause of the death of many men, including Ekweme. Besides the aforesaid, abandonment of a spouse takes many forms and could be result of many causes in world mythologies.

Elechi Amadi, The Concubine, Heinemann, 1966.