Scarlett Johansson has said it “isn’t natural” to be monogamous. She claims it’s too much like hard work, and continues, “the fact that it is such work for so many people … proves that it is not a natural thing. It definitely goes against some instinct to look beyond.”

I think that she may have something of a skewed perspective on monogamy. When you are one of the most beautiful and highly paid actors in the world, it may be that the temptation to “look beyond” takes on a more concrete form than it does for someone working on a jam doughnut production line in Woking. The often-unacknowledged reality about monogamy is that it frequently has less to do with integrity and more to do with demand, supply and opportunity. I am always amused when I hear deeply unalluring American evangelical preachers boasting about their lifelong fidelity. As if most of them have a choice.

I have not been inundated with offers – somehow a wedding ring and four kids is not an immense aphrodisiac for most

I have been monogamous during my two marriages, but I’m not sure that it’s entirely about my extraordinary powers of self-control. Truth is, I have not been inundated with offers– somehow a wedding ring and four kids in tow is not an immense aphrodisiac for most. Johansson equates “monogamy” with “work” – probably because she doesn’t spend a lot of time vacuuming behind the sofa. Whatever the case, I know what she means. It’s not staying faithful that’s difficult – it’s staying at all. Putting that to one side, isn’t infidelity ultimately about ego – for both parties? One is trying to boost their ego, one feels their ego has been destroyed if their partner has strayed.

That your partner should only ever fancy you seems unrealistic. That your partner should only ever have sex with you seems fair enough – I suppose – although it’s probably rooted in convention as much as anything else. But does it really matter – if your partner never finds out? And even if they do find out, does that, in turn, truly matter? Isn’t it just the case that the self-image of the injured party has been shattered?

Worse than the idea that the material symbol of privacy and intimacy – access to your partner’s body – has been betrayed, is the dishonesty that is inevitably involved. To serially lie and conceal the truth about matters is the truly corrosive aspect of infidelity – and in most cases, the most hurtful thing. Because intimacy, surely, is about secrets. Although I have been faithful, I have been accused of having “emotional affairs”. I did, during my marriages, have intimate platonic relationships with other women, and men. For some, this counts as a form of infidelity – although I find that concept of equivalence doubtful. “Having secrets and confessing them is what deep attachments are about,” writes the great Harold Brodkey. He continues, “Telling the truth is never wholly recommended, however.” That paradox sums it up. Telling the truth if you’re having an affair is probably even worse than lying.

But lying is pretty bad, too. I could say, “Well, just don’t have an affair in the first place,” but there’s also a telling moment in Jonathan Safran Foer’s latest novel, Here I Am – about the breakup of a marriage – when the wife says, convincingly, to her timid husband that she would have respected him more if he had had the guts to have an affair rather than just fantasise about it. And I get that, too.

You can’t win, really. It’s one of the great examples of how limitation of choice can make things a great deal easier – because it’s not a problem that’s going to be vexing me much in the immediate future.

Perhaps it’s one of the few advantages of getting divorced. I haven’t even got an opportunity to be monogamous, let alone unfaithful. So perhaps whether Scarlett Johansson, scutty evangelist or Woking factory worker, one should be grateful for small mercies.

@timlottwriter