IF you read my post you will clearly see that IF a woman is denying her husband sex (you heard on the grapevine??? Really???) then I suggested counselling for both. If she refused then I would advise that he was honest and open with her and if necessary, the relationship is brought to a close.
No-one denies their partner sex unless there is a very good reason behind it, i.e. depression, medical problem, etc.
You will also note that I said affairs are not just about sexual fulfillment. It is about the betrayal, the lying, the secrecy, the deceit. You have chosen to ignore all of these.
You say that if a party cannot get sex from within their marriage then it is within their rights to be deceitful and seek that fulfilment outside the marriage? Really? If you couldn't have sex for whatever reason, how would you react if, instead of talking about it, your dh went off and shagged someone else? Even worse, he shagged another married woman whose poor sod of a husband doesn't know either.
I shall repeat DECEIT, LIES, BETRAYAL are the reasons that marriages breakdown after an affair. Because marriages are all about RESPECT, COMMUNICATION, HONESTY.
If you aren't happy in your marriage then you'll either try to fix it, or if it cannot be fixed then you bring it to a close, allowing you and your partner to find happiness with someone else. You don't sneak around wrecking lives.