Updated, now with bicontinental idiocy.
The old cliche seems to be true, at least for French socialists [sic] and neocons. From the London Daily Mail:
France’s First Lady three-timed husband with the President and married right-winger (and the rival politicians KNEW they were sharing a mistress)
And from Boing Boing on this side of the pond, stupid Republican sex tricks:
Anti-choice Tea Party Congressman pressured pregnant mistress to get an abortion