John Hardly,
I don't think Clinton fully "survived" the "Monicagate" or other "sexual scandals." First, his legacy will always be tarnished by having "impeached" and the various allegations cited in historical records, probably in many ways overshadowing his accomplishments (e.g., turning a deficit economy into a huge surplus). The Democratic party also took a big hit because of the brouhaha over Clinton's private sex life. Al Gore would almost certainly have won in a landslide in 2000 had it not been for the impeachment, the Starr Report, etc.


As for "Republicans who have left in sexual scandal:
Foley
Craig
Livingston
Bauman,"

let's not forget that
a) Rudy Guiliani, Newt Gingrich, and others have been guilty of adultery, sequential marriage, etc., and remained quite viable in the Republican party. Strom Thurmond even got by with having fathered a child by a black woman even while being actively racist in his public life.    The Republicans never seemed interested in delving into that.

b) Those 3 Republicans had more involved than just "sex" or "adultery" or "being gay." Foley's misdeeds were homosexual (a big no-no to his own party) and involved pages or other Congressional employees (so sexual harrassment and/or abuse of a minor may have been issues). (Had there been reason to believe Clinton initiated the affair with Monica, he probably would have been charged with workplace sexual harrassment too, but she pretty clearly planned it herself.) Plus, Livingston pretty much had to resign over his revealed affair because he had been going after Clinton with such a vengeance (holier-than-thou). Had he not attacked Clinton for his adultery, Livingston's own would probably never have been an issue.

And as for Democrats like Barney Frank and Bill Clinton not having been pressured to resign, maybe that's partly because of the overkill on the part of the opposing party and the media? And, as we've said, partly because Dems don't tend to make a BFD out of what consenting adults do in private?