At the beginning of this poignant novel, Ramatoulaye's husband has just died. As if that were not traumatic enough, she must share her home during these days with Binetou, her husband's second wife, who is her daughter's age. In this situation, Ramatoulaye starts to think with bitterness about why her late husband, Moudou, had compelled her to become a co-wife after many years of marriage and many children. The theme of betrayal is important here because if her husband had not taken on a second wife, Ramatoulaye would just have been grieving her husband, without the added complication of the bitterness that she felt towards him.

The ironic part of this was that as a young woman, Ramatoulaye had been well educated and had her choice of husbands. She picked Moudou because she loved him, and despite polygamy being allowed in terms of Senegalese tradition, she had been devastated when her husband became a "sugar daddy" to one of their daughter's friends.

His betrayal didn't stop there either. Following his marriage to his second young wife, Moudou stopped providing for Ramatoulaye or any of their children.

I would argue that the importance of betrayal is further exemplified by Ramatoulaye's refusal to marry Daouda Dieng in the aftermath of Moudou's death. Having experienced betrayal and all the pain that comes with it, she simply refused to put another woman through that.

The betrayal that she went through influenced Ramatoulaye's behavior by making her defensive, both for her rights and the rights of other women.

It’s no exaggeration to say that Ramatoulaye’s betrayal at the hands of her late husband Moudou has had a damaging impact on her life. Whereas many other Senegalese women in her position would be expected to accept such behavior as coming with the territory, Ramatoulaye didn’t accept it during her husband’s lifetime and she’s even less accepting of it now that he’s dead and gone.

Somehow, Ramatoulaye managed to pull her life together after Moudou abandoned her and married a younger woman. But it’s perfectly clear from the tone of her letter to Aissatou that she’s never really got over the experience; she’s understandably bitter about the whole thing and feels much less able to trust anybody.

But Moudou’s betrayal didn’t just come out of nowhere. To a cancelable extent, it’s the product of the prevailing system of polygamy, in which men can have many different wives at the same time. Even though husbands are supposed to treat all wives equally, in actual fact they tend to have favorites, as in the case of Moudou with his young bride. Far from protecting women, or encouraging a more respectful attitude towards them, polygamy actually incites betrayal, neglect, and abandonment, as Ramatoulaye knows all too well.

Mariama Ba's So Long a Letter is a semi-autobiographical novel inspired by experiences of abandonment.

The story takes the form of a letter written by Ramatoulaye to her best friend Aissatou Ba, in which she conveys her heart-wrenching journey of betrayal. She remembers how her husband betrayed her several years ago, by marrying a much younger woman and abandoning her and her children. Ramatoulaye suffers emotional trauma and conflict. She considers herself a feminist and is bound to traditions too. She wants to divorce her husband but decides against it.

Ramatoulaye's friend Aissatou experiences betrayal in her marriage. However, she chooses to react differently. She stands up to a society ridden with patriarchal hypocrisy. She refuses to be in a relationship that degrades her. She moves on with a new life that does not involve polygamy.

The story celebrates feminists who do not succumb to cultural betrayal and endeavor to reclaim their respect and dignity.

Betrayal is seen throughout the story in the customs of the Sengalese people. Husbands are expected to take more than one wife, and it is a shame to the husband's family if he doesn't, as is the case with Aissatou, the woman to whom Ramatoulaye is writing. Aissatou's mother-in-law forced her son to take a second wife, and Aissatou saw this as a betrayal of her husband's love for her, so she divorced him. In her case, Aissatou is betrayed by both her husband and her mother-in-law. Ramatoulaye stays married to her husband after he takes a younger wife and abandons Ramatoulaye and her children. She doesn't allow her anger of her husband's betrayal to emerge until after his death. It is then that she shows the strength to be able to refuse marriage to her husband's brother and an old boyfriend who stilled loved her. She knew she could never inflict the pain on other women that she had felt when her husband took another wife. Throughout the story, Ramatoulaye is conflicted about the traditions of Islam and her society. Her religion comforts her in one aspect, but she recognizes how unjust polygamy is. Her behavior is based on this conflict until the end, when she's able to come to terms with how she feels.