“What makes you think that it isn’t an open marriage?”
Personally, I assume marriages are closed unless told otherwise, as that’s the standard meaning of marriage.
“In any case, that is a personal matter between them IMHO.”
Not in mine. There’s the character issue, but nevermind that. With all the talk about privacy and do your own thing and blah, blah, blah the last few decades, we tend to forget that marriage is a very public thing. Perhaps the most public thing about most people. If you don’t want people to judge you for your sexual proclivities, you can have as much privacy as you can muster. But should they be discovered, don’t plead “Who cares?” after standing up in front of the community and pledging yourself to another.
Again, marriage doesn’t necessarily mean that. But most everyone thinks it does, and you should know that going in.
Seem to forget? Study American history. American presidents who had affairs are all over the place. If your goal is to find such a candidate, especially in the political class, you might as well abstain from politics.
BTW, I support a candidate who has a loving marriage of more than five decades and who has never been accused of having an affair: Ron Paul.