Another day, another politician outed as an adulterer. This time, the story will likely not fade from the headlines at the usual rate. This time, the adulterer is Arnold Schwarzenegger, who doubles both as the former governor of California and a major movie star. To make the situation still more lurid, he cheated with a servant, had a child with her, and covered it up – apparently, even from his wife – for a decade.

Oh, did I mention that he's married to a member of the Kennedy clan, Maria Shriver? And that she's a prominent feminist activist? And that she used her credibility as a liberal feminist Democrat to cover for him when he admitted to decades of sexual harassment during the 2003 campaign, when he was also exposed for participating in the 70s in what, by his description, sounds suspiciously like a gang rape? And that while his wife was out there working on behalf of women, Schwarzenegger was taking the time to rail against the evils of single motherhood? You know, just to make sure that no future would-be defenders of his bad behaviour could claim, "At least he's not a hypocrite."

If you presented it as a novel or a film script, you'd get it bounced back with a note that said, "Try to make it believable."

But despite the craziness of this particular situation, the basic story of the adulterous politician has become commonplace. Is there any situation more confounding in politics than the exposure of adultery in the ranks of ambitious politicians? Once or twice, you expect a man (and they are mostly men) to screw up and get caught, but the endless parade of cheaters and cads defies common sense. Why, your average voting citizen asks, would someone who has given his entire life over to striving for power risk everything for some fleeting sexual experience? Why, especially, do those men who fancy themselves not just political but moral leaders so readily make exceptions for their own peccadilloes?

Most of us will never know, because most of us aren't wealthy members of an elite class who have been pampered into forgetting that you can't have whatever you want whenever you want it. For most of us, cleaning our own houses, cooking our own food and having to fly coach provides a daily dose of humility – which can be a helpful thing to keep in mind when sexual temptations present themselves.

To make it even worse, even the more liberal-minded male politicians not only have this kind of class pampering, but they also tend to live in a world where women are easy to take for granted. For many a male politician, women appear to exist for the purpose of making your life more pleasant and your ambitions easier to realise. It's not just that women are more likely to fetch your food, fluff your pillows and organise your life while you sit around talking politics and strategy in male-dominated groups of strategists and advisers. It's also that your wife has been demoted from a partner to your top cheerleader, expected to compromise her principles and ambitions so you can attain power.

Maria Shriver is a perfect example of the way that the role of the political wife demeans and objectifies women. During the 2003 gubernatorial race in California, when Schwarzenegger was buried under a stream of allegations of sexual harassment, Shriver used her substantial reputation as a powerful, feminist woman as a shield against allegations levelled at her sleazy husband. When a man like Schwarzenegger lives in a world where women are so subservient to him that they throw their reputations away for his political ambitions, it's no surprise that he can't muster the basic respect for women required not to horndog the servants behind his wife's back.

To be clear, there are two camps of egotistical politicians who cheat so stupidly, and the two should not be conflated: those who value consent and those who treat women like sex toys they can grab at, with little regard for what the women in question feel on the subject. Men like Bill Clinton and Newt Gingrich are cheating cads, but they, as far as we all know, draw the line at violence against women. Unfortunately, when you build up a culture of overwhelming male entitlement such as politicians live in, you can't expect all of them to understand that, while cheating and lying is bad, harassing and assaulting is exponentially worse.

This is something to keep in mind when contemplating the Schwarzenegger situation, and his long and admitted history of harassing women that predates these revelations. But it's also something to keep in mind with regard to the charges of rape, sexual assault and unlawful imprisonment against the IMF head Dominique Strauss-Kahn. Whatever the outcome of his case, there is no excuse for those who fail to distinguish between actual assault and caddish but consensual behaviour. Conflating the two only amplifies a culture of entitlement for those living the low-responsibility elite lifestyle, blurring the line between treating women poorly and treating women criminally.