It's not always easy for some stars to stay faithful -- or to keep their secrets hidden.
The world was shocked in May 2011 when Arnold Schwarzenegger and Maria Shriver announced their separation after 25 years and four kids together -- but fans of the actor and governor were floored when it was revealed that the star, 63, fathered a secret love child, now 13, with a household staffer.
Five months later, another A-list marriage also went down in flames: the six-year union of Ashton Kutcher and Demi Moore, rocked by 33-year-old Kutcher's revealed fling (on their sixth anniversary!) with Sara Leal.
Leal, 22, opened up to Us Weekly about her wild night with the Two and a Half Men star, who claimed he was separated from Moore, 49, before seducing her in a hot tub. (Moore announced the end of their marriage in November.)
Other high-profile figures -- including former Congressman Anthony Weiner -- were also grilled in the public eye for adulterous moments, while rumors swirled about such couples as Will and Jada Pinkett Smith, Marc Anthony and Jennifer Lopez, and more.
Perhaps the most surprising star linked to a cheating scandal? Jennifer Aniston, who reportedly pursued Wanderlust costar Justin Theroux -- in spite of his 14-year relationship with live-in love Heidi Bivens.
Look back on the biggest cheating scandals of the year and tell Us -- which shocked you the most?