I Wish You Had Called

Alice and Bob are in a loving relationship. Bob visits Alice unexpectedly, Alice tells Bob "I wish you had called..." Turns out, Alice was cheating on Bob, and didn't want Bob to find out like this (or at all).

A non-romantic variant exists when Alice is simply doing something embarrassing and wishes Bob called so she wouldn't be caught unexpectedly.

Live Action Television

 * Friends had Chandler show up at his girlfriend's place after he accused her of cheating. Turns out that she was driven to cheat after he accused her and she says this.
 * Spoofed in an episode of How I Met Your Mother. Barney and Robin show up on Marshall and Lily's doorstep to apologize for avoiding them, only to find Marshall and Lily with another couple. Double dates are basically portrayed as essentially the couple dating the other couple in this scenario.