@randomneuralfirings – Right, like John Edwards, Elliot Spitzer, Bill Clinton, etc… the media totally left those guys alone and never mentioned their party affiliations and none of them suffered any consequences. There’s this little thing called confirmation bias – beware of it.
Anyway to answer the question in the post – no, he shouldn’t have to resign. I could care less what politicians do in their personal lives. And in fact, he doesn’t HAVE to resign at all; this was his choice.