I believe that there is not only a biological basis for the parallel, but that the level of harm to oneself and others is commensurate. It was a bad decision. A mistake is something you do on accident, that you would not do purposefully. A terrible personal mistake would be something like pulling your car out of your driveway and running over your child. Sex between consenting adults, in and of itself, does not qualify.
Sexuality is a powerful force.
If every cheater in America had their professional and personal life destroyed, we would be a nation of failures. Not all people, but enough for me to say that this is a completely normal occurrence, and does not merit my outrage. To a great extent, I am of the Larry Flynt school of sexual politics, though I would take it a step further than he has to date. I would include the media in a clean sweep of hypocrisy regarding sexual behavior. So, if a Brian Williams or a Peter Jennings wants to get their boxers in a twist over Clinton's or Jackson's sexual behavior, then I want to know they are not projecting their own self-loathing onto these two.