Mind Moves: The other woman features prominently in drama and literature. She is the hidden presence of whom the reader, the audience, the viewers are aware, while the wife remains ignorant of her existence. Or so it is for a time.
Many novels and plays hinge their plots on either the gradual realisation or dramatic discovery by the wife that she is the subject of deception. Classic characterisation represents the other woman as cold-hearted, opportunistic and determined to undermine a marital relationship for her own gain.
Wives are depicted as naively unconscious of their predicament. They are contented commodities, as functional and comfortable as a soft slipper while the other woman is portrayed as the stiletto of sexuality, duplicity and guile.
Wives are often depicted as pathetic for not acknowledging the predatory propensity of their gender and protecting their mates. It is, of course, impossible for wives to compete with the unknown, in a competition of which they are unaware, fighting against indeterminate odds on an unequal playing field.
But wives are not the only people who are pathetic in this love triangle, because the other woman is often equally, subsequently dismissed, if she wins the contest, marries the man and becomes the new wife.
Worse still is the relinquishment of any real personal life for those women who remain the mistress for years and years in a macabre alliance that continues to the grave.
Of course for a few women, being the other woman is favoured for the power it provides over other women's lives, or the thrill of clandestine couplings. Such women know that the men with whom they have affairs are neither courageous nor trustworthy and they use them in equal measure to the way they are used. For how could any other woman believe the man she sees deceive the person to whom he once pledged lifelong love and care?
Many men also say that it is the affair more than the other woman that attracts them. Intrigue is the context within which the triangle is fixed, wherein the power differentials between the women are set and the man holds ultimate power.
He is the one who will choose between two women - at least one of whom is unaware that her fate is subject to his whim. He will decide which woman he spends time with; how, where, when, in what way and with what level of secrecy, visibility, blatancy or restraint he will conduct the affair. He must continuously con one or both women: one woman more than another or each of them in different ways.
For in the traditional triangle, the husband is the only person in the triad who knows exactly what is happening in all the contexts of his life. His wife may wonder if such late working hours and client entertainment are absolutely necessary.
The other woman may torture herself about his home life - whether his wife really does not understand him as the cliche proclaims, or whether the affair is an amusement and she will also be cast aside as carelessly as his marriage.
He is the one who knows. He knows which explanations he gives to each woman are lies and which are not. He knows where he is going when he departs from either woman; on whom he spends most money; what he has not told the other woman about his life with his wife; when, if ever and in what manner he will eventually tell one woman that he is leaving her and who that is most likely to be.
And here lies the story that is less often told: the story of the other woman who remains the other woman all her life. Because very occasionally the other woman lives out her life in a relationship with a married man until death do they part. If he is the departed one, she is in the most invidious position: grieving a relationship that no one may even know she has lost.
On the clinical horizon there sometimes appear these other women who relinquished their liberty, their youth and their marriage prospects for life as the other woman. They may have forgone the chance to have children, to be seen publicly with their man, to be invited as a couple to social events.
They will have had no right to be with him at critical family times - Christmas, Easter, Valentine's Day and all the milestone celebrations in his children's lives. They will have been alone when couples are traditionally together, or timing each meeting, arranging alibis in their social circles, feigning indifference in interactions if they meet, editing their lives to support the subterfuge, subverting their true selves in the service of a parallel partnership, at the end of which they are absolutely alone.
Should he become seriously ill they have no right to visit, to be informed of his condition, spend time with him in later years, be at his deathbed, receive recognition, sympathy and respect when he dies and/or resolve their loss of a partner in the usual way.
In the fictional world the play ends, the screen credits appear, the book is closed, the poem is complete, the triangle untangles, the triad becomes a dyad (two) or death finds one or other woman by the graveside wondering where it all went wrong.
Reality is less romantic, more mundane and worth consideration by young women as to what previous rejections, psychological predilections, adrenaline addictions or morbid fears cause them to choose the clandestine above committed relationships in their lives.
Marie Murray is director of psychology at St Vincent's Psychiatric Hospital, Fairview.