More and more people are coming forward on social media platforms including Reddit to share their experience about ‘cuckolding’, which as become increasingly popular over the years.

Cuckolding is the term used when men encourage their wives or girlfriends to participate in a sexual encounter with other men. While most people would see this act as cheating, there are those who point out a distinction when it comes to cuckolding.

For one man it was a “pure unfiltered sexual thrill” when he witnessed his girlfriend having sex with another man, The Sun reported. While others felt an “intense” sexual thrill when their women refused their advances.

So what is the real drive behind it? Some psychologists suggest that it could be male bisexuality that is repressed or a partners’ sexual freedom is appealing.

However, Dr David J Ley author of Insatiable Wives: Women Who Stray and the Men Who Love Them, sees the motive as being much more simple.

Watching their partner getting a thrill from another man may be associated with breaking the traditional relationship rules, which is turns them on.

“When an otherwise well-controlled heterosexual male dares to visually create his wife’s violating her marital vows, and possibly his even encouraging her to do so, he’s playing a vital role in what we might call a ‘double transgression’ of society’s norms,” Dr David J Ley told Psychology Today. He also feel these “forbidden fantasies” could be gratifying.