Love Actually
One of the most notable moments of Love Actually is when Andrew Lincoln's character confesses his feelings to Keira Knightley's character, who happens to be his best friend's wife. This is the cue card moment, which is actually quite weird in reality but it seemed to have worked out in the film. Andrew Lincoln himself even said this was weird for him!
American Hustle
Con artist Irving Rosenfeld (Christian Bale), his partner and mistress Sydney Prosser (Amy Adams), and his wife Rosalyn Rosenfeld (Jennifer Lawrence) are crazy characters in American Hustle. There's never a dull moment in this film, and the scene where Sydney and Rosalyn share a kiss took viewers off guard! How many times do the mistress and the wife get together, anyway?