Previous research has suggested that nearly 1/3 of all people in a relationship get cheated on at least once. But when it comes to friends betraying one another by sleeping with their sisters and moms? Thankfully, there isn't enough research to properly assess that kind of unfaithfulness yet. Although a video recently surfaced that suggests a new category for the dirty deed may have just been established. 

Scroll up and press play to see how this man reacted to walking in on the bedroom exploits of his friend, mom, and sister.

Source: YouTube