At least old-fashioned philanderers knew where they stood. For them, only an extramarital affair was considered cheating. In the modern, digital age, however, it takes an awful lot less to wreck a relationship.
Welcome to the world of "micro-cheating".
According to academic Martin Graff, all it now requires is the click of a computer button for a partner to be considered unfaithful. "Micro-cheating" describes behaviour that falls into a grey area between friendly interaction and infidelity. Examples of micro-cheating include checking the social media accounts of former partners; sending emojis such as hearts and flowers to people other than partners; and saving mobile phone contact details of a friend of the opposite sex under a false name.
In short, showing a high level of "digital" interest in someone outside the existing relationship can constitute micro-cheating.
"It can be something as simple as repeatedly 'liking' someone's posts on Instagram or commenting on someone's Facebook," says Graff, a reader in psychology at the University of South Wales. "So much of human relationships has moved online," he says, meaning couples now have to make decisions about what is acceptable online that they didn't have to make 10 years ago.