 I'm Sam Blakney and the author of Malignant Self-Love, Narcissism Revisited. What should you do if your husband is a narcissist and is having an extramarital affair? He's cheating on you and betraying your trust. Well, the answer is that narcissists are people who fail to maintain a stable sense of self-worth. Very often, somatic narcissists, if they are narcissists who use their bodies and their sexuality to secure narcissistic supply, tend to get involved in extramarital affairs. The new sexual conquests sustain their grandiose fantasies and their distorted and unrealistic self-image. It is therefore nigh impossible to alter this particular behavior of a somatic narcissist. Sexual interactions serve as a constant, reliable, easy-to-obtain narcissistic supply. It is the only source of such supply if the narcissist is not cerebral. In other words, if he doesn't rely on his intellect, intelligence or professional achievements for narcissistic supply, pure somatic narcissists de-emphasize their intellectual capabilities in favor of their physical attributes, sexual prowess and ability to coca the opposite sex or the same sex in case they are homosexuals. Well, one way of coping with this situation is that you should set up rigid, strict and very well-defined rules of engagement. Ideally, all contacts between your spouse and his lover should be immediately and irrevocably severed. But this is usually too much to ask for. So you should make crystal clear when is she allowed to call, whether she is allowed to write to him at all and in which circumstances. What are the subjects she is allowed to broach in her correspondence and phone calls? When is he allowed to see her and what other modes of interaction between them are permissible? Clear and painful sanctions must be defined in case the above rules are violated. Both rules and sanctions must be applied rigorously and mercilessly and must be set in writing in unequivocal terms. Fairness is important, but so is rigorousness and strictness. The problem is that the narcissist never really separates from his sources of narcissistic supply until and unless they cease to be sources. Narcissists never really say goodbye. The narcissist's lover is likely to still have an emotional hold on him long after the affair is officially over. The husband must first have his day of reckoning with her. Help your narcissistic maid or husband or intimate partner by telling him what will be the price that he stands to pay if he does not obey the rules and sections that you have agreed upon. Tell him that you cannot live like this any longer, that if he does not get rid of this presence of the echoes of his past, really, he will be squandering his present. He will be forfeiting you. Don't be afraid to lose him. If he prefers this woman to you, it is important for you to know it. If he prefers you to her, your nightmare is over. If you insist on staying with a somatic narcissist, you must also be prepared to serve as a source of narcissistic supply, an alternative to the supply provided by his lovers. You must brace yourself. Serving as a source of narcissistic supply is an honorous task, a full-time job, and a very ungrateful one at that. The narcissist thirsts for adulation, admiration, worship, approval, and attention can never be quenched. It is a Sisyphean mind-numbing effort which heralds only additional demands and disgruntled, critical, humiliating tyrants by the narcissist. That you are afraid to confront reality is normal. You are afraid to set clear alternatives. You are afraid that he will abandon you. You are afraid that he will prefer her to you. And you may well be right. But if this is the case and you go on living with him and tormenting yourself, it is unhealthy. You are living a deception. If you found it difficult to confront the fact that it is all over between you, that your relationship is an empty shell, that your husband or intimate partner is with another woman in the fullest sense of the word, do not hesitate to seek help from professionals and non-professionals alike. Friends are a great source of support and assistance. But do not let the situation fester into psychological gangrene. Amputate now while you can.