Gays in marriages

Recently there has been some interest in the phenomenon of women who are married to gay men. I assume the focus is a reaction to the portrayal of two such couples in the film Brokeback Mountain.
The New York Times ran a story about it:

Helen Fisher, a research anthropologist at Rutgers University, said in an interview that human partnerships are shaped by three independent neurochemical brain-body systems, responsible respectively for sexual attraction, romantic yearning and long-term attachment.
"The three systems are very fickle. They can act together, or they can act separately," Dr. Fisher said. This, she said, helps explain why people can be wildly sexually attracted to those they have no romantic interest in, and romantically drawn to — or permanently attached to — people who hold no sexual interest.
"Once the system is triggered, it's so chemically powerful that you can easily overlook everything about that person that doesn't work for you," Dr. Fisher said. "Even straight people have fallen in love with people they could never make a life with," she said.

The (London) Times also published an account (via Tim Worstall) of a person who had to face this issue (albeit shortly before the wedding):

But even if Mr Normal decides that he is bisexual — or even straight — could I ever forgive his betrayal? A close male friend of mine said I was looking at it wrongly, that it wasn’t about betrayal and forgiveness. "The trouble with women is that they think everything is about them. They love martyring themselves. If their boyfriends cheat on them, they think 'What's wrong with me?' But it has nothing to do with them. Most blokes need a lot of sex, and want a wide variety of sex. When they cheat it’s about them and their weakness, it’s not about you."
I don't agree. It is about you, it's about the fact that your partner goes ahead and does something that he doesn't need, but wants, knowing full well that if you find out you'll be devastated. In other words, he doesn't care about you enough to forgo something for your sake. Regardless of where you fall within the straight-bisexual-gay continuum, I would have said that betrayal is betrayal.
But having talked night and day with this man, I have come to the conclusion that there might be an exception to this rule: the person who is truly in denial. A person in denial can't betray you, because he doesn't know what the truth is himself. If he betrays anyone, he betrays himself, and by comparison you're a minor casualty. Unless you know someone in denial, you probably have no idea of the power it can hold over a person. An alcoholic who is truly in denial does not lie to you when he tells you he does not have a problem with booze, he really believes he hasn't got one. He’s running away from what he sees as the awful truth of himself so fast that it has become a blur.

Perhaps being in denial is an extenuating circumstance. However most of all I agree with the author's point about betrayal. In fact, two thoughts spring to mind:
1. I find it deeply offensive to say that people have such a limited control over their emotional and sexual desires and impulses. I think "betrayal" cannot be justified by claiming "irresistible urges." Chemical imbalances?! Puh-leaze!
It is eminently possible that this view depends on my personality (which has been defined "icy" – though I, and hopefully those who know me best, would dispute that). Even so, it seems to me that if there are people who have such irresistible sexual drives, they should refrain from marrying – and if they have married, and are unwilling to divorce, they should make the effort and forego the fulfillment of these urges instead of forcing the rather sordid situations described in the articles above, on their spouses.
2. The other thing I found mildly odd is that the discussion in the media only centers on straight women married to gay men, while undoubtedly the opposite also exists: straight men married to lesbian women. True, this phenomenon is surely not as common (actually, the whole phenomenon is probably rarer than claimed, as Tim Worstall points out) but I still think it worthy of note that women always seem to be projected as the victims (in this respect and in others), while this is clearly not necessarily the case anymore (in the West).