30. Alexis Bledel and Vincent Kartheiser

In 2012, Alexis Bledel was a guest star on season five of Mad Men, playing the mistress of Vincent Kartheiser’s character, Pete Campbell. Although they played out an illicit affair on-screen, their relationship off-screen is much more faithful. The two began dating after filming wrapped, and they very discreetly got married in 2014. 

The couple is famously discreet and private, preferring to keep details of their relationship away from the prying eyes of the public. Jon Hamm, Kartheiser’s Mad Men costar, said he could sense the attraction between the two actors almost immediately on set. They are still happily married and recently welcomed a baby boy to their family!