'I was checking out the nurses'

Two years ago, when his wife Kirsten was diagnosed with breast cancer, Brendan Halpin found his eye wandering. It was not the first time in his married life that he'd admired other women, but it was, he admits, by far the most extreme. "Being married doesn't shut off your ability to be attracted to other people. When your wife has cancer it gets even worse." In this, it turns out, he is not unusual: former Republican House Speaker Newt Gingrich, after all, famously served his wife divorce papers while she was in hospital awaiting chemotherapy. And, on reading in Halpin's new book of his struggle with his testosterone, other American men have sent sympathetic messages. "In their e-mails they say, 'And I thought I was the only one checking out the chemo nurses.'"

There must, Halpin figures, be "a primal thing going on, something to do with looking for a replacement". The difference between Gingrich and Halpin, however, is that the latter - a 33-year-old Boston highschool teacher - did not act on his desires.

Instead, he chose to channel his energy, fear and raging insomnia into writing a book about the experience. To the "A" side as portrayed in books such as John Diamond's C, and Ruth Picardie's Before I Say Goodbye - in which the authors chronicled their own struggles with the disease - Halpin's It Takes a Worried Man is the oft-forgotten "B" side. It describes the roller-coaster ride when your dearest is diagnosed with cancer.

Halpin confesses that his approach resulted in him being accused of "self-obsession". But, while admitting that "it is proper that the focus should be on her, since she's the one fighting for her life", he states that "it's been a very difficult time for me, also. I'm not saying that it's the same: unlike her, I knew that I was going to be alive at the end of the treatment, but my world had certainly been turned upside down. The act of writing - spending an hour or two a day to focus on myself - certainly helped a lot."

Those who've carped at him for navel-gazing missed one crucial fact: it was Kirsten's idea that he should set pen to paper. This was very deliberate, she confesses later. "I honestly didn't have time to listen to him saying, 'I'm so worried about losing you'. It sounds horrible, but I was the one staring into the abyss. I didn't have any time to pat him on the back. He's always found an outlet in his writing, so I suggested that he write it down. He started doing it and immediately began to feel better." Twenty-two months on from the start of her treatment - which included aggressive chemotherapy and a mastectomy - Kirsten, now 34, is in remission.

She seems a calm, almost ethereal presence, accompanied by their five-year-old daughter Rowen. Now on lower-strength weekly doses of chemotherapy, her curly auburn hair has grown back. Halpin's hair, by contrast, remains buzz-cut.

He first shaved his head when Kirsten lost her locks to chemotherapy. It was a gesture of solidarity. "It felt like the least I could do. There's really so little you can do to help, and there's such a desire to do something. It was a symbol that we're in this together."

When hers grew back, he imagined he'd let his do the same, although this now seems inconceivable. "I'm not the same person any more. It's not as if I'm looking for an external symbol, but whenever my hair starts to get long it feels wrong. It's like I'm pretending to be the guy I was before."

Fear of death has always haunted Halpin, but it was always his own premature demise that he worried about, not that of his wife. His father died aged 35, when Halpin was nine. "He went out to cut some wood one day and never came home: a pulmonary oedema. For a long time I lived in fear that this was going to happen to me." Now, he jokes that Kirsten's cancer has "made me think I'm immortal", and he is concerned not that he will die prematurely, but rather that he will end up "like my mom", with whom, as her only child, he has a somewhat claustrophobic relationship. During the most intensive phase of Kirsten's treatment, however, he did his utmost to be positive. "What I felt most guilty about in that period was not finding other women attractive but imagining what my life would be like if she was dead. That felt like a serious breach of faith. It was my job to be the peppy cheerleader, to really believe that she would come through." Cancer specialists, he says, offer very little solace. "I don't know whether it's because they're afraid of being sued, but it's really hard to ever get a positive word out of them."

His fellow teachers and teenage students, however, were far more supportive: to pre-empt questions, he wrote them all a long email. This explained the extent of Kirsten's cancer, the treatment options, and offered answers to such frequently asked questions as: "How are you holding up?" and "What can I do?" To the latter, he suggested blood and platelet donations, and prayer.