Micro-cheating, as the name suggests, stops short of physical infidelity. Photo / Getty Images
Within a few months of meeting at a party, Nadiya and Ryan, an old friend of her family, were messaging each other up to 35 times a day.
"I was living with my fiance and I should have ended it, but I wanted to continue the excitement," says Nadiya, 30.
"I went as far as getting a secret phone because I didn't want my fiance to find out. But even at this point, we never said anything sexual to each other.
"Then, after around six months, I realised Ryan was feeling more attracted to me. I loved the attention, but he was saying things like: 'Can I come to see you?' Part of me was thrilled by it. But I knew I loved my fiance and didn't want to cheat on him.
"I made the decision to end it, and turned off my secret phone. I left it for about a week, then I turned it on again and up popped loads of messages from him saying: 'Where are you? Why can't we be friends?' I simply replied: 'I can't do this any more.'
"That was it. It was hard and I missed the flirtation and the excitement, but I didn't want to get caught."
At first glance, it's hard to know how to assess Nadiya and Ryan's relationship. It was more than a friendship, but not overtly sexual and never physical.
I believe what Nadiya is admitting to is micro-cheating, a term I've used in my work as a research psychologist to describe online behaviour that falls into a grey area between friendliness and infidelity.
Micro-cheating, as the name suggests, stops short of physical infidelity. However, there will be some who will see it as a way to look around for potential partners, so it could end up being the first step to a physical affair.
For others, it won't even go so far as what's termed "an emotional affair", when a person shares intimate thoughts with someone outside the marriage, or relies on someone who isn't their partner for emotional support. For them, it's simply an online flirtation.
In the same way that the internet has made it easier to initiate full-blown affairs, micro-cheating is something that's become increasingly prevalent as a result of our ability to connect with multiple people a day via social media, messaging apps and texts.
It's estimated the average user is spending 50 minutes on Facebook each day, managing contacts across an average of four social networks, such as Twitter, Instagram and Facebook.
Our understanding of what constituted infidelity in the past was pretty clear cut. But in a world with ever more fluid social codes and informal ways of connecting, the rules of what's acceptable between two people who are not in a relationship are more open to interpretation.
My research into micro-cheating set out to clarify what online behaviour men and women consider to be unfaithful - or even disrespectful.
I put different scenarios to people to judge whether they considered the people involved to be cheating. I found that women have a much narrower definition than men of what they consider acceptable.
Take emojis.
Many people sprinkle emojis on every Facebook post and text message, no matter whom they are addressing.
And yet, some of the women I spoke to would class their partner putting an emoji of a heart or flowers on another woman's Facebook page as inappropriate.
Furthermore, some consider it cheating behaviour if a person tags a former lover in a post as part of an inside joke, or if they regularly check the social media accounts of former partners.
For others, even basic digital interactions can be a sign of micro-cheating. These include things that many of us would do without a second thought, such as inviting an ex to be a Facebook friend or, if in a heterosexual relationship, messaging someone of the opposite sex without telling our partner.
Time of day can be key. Someone who messages an ex, or a colleague, in the morning to share news may be viewed as having different intentions to someone who is messaging that same person late at night.
And what you share is important, too.
The women I surveyed were less bothered if their partners were sharing factual information with other women, but objected when conversations involved feelings.
Some behaviours are more likely to raise suspicion than others. An acquaintance once admitted that he saved the details of female friends under men's names when he added contacts to his phone.
He insisted there was nothing untoward about this habit, but it was hard to see how his wife wouldn't class this as suspicious.
It's also common for women to end messages to female friends with kisses, and some now also finish messages to men this way. Is this micro-cheating or just harmless affectation in our informal digital age?
What makes the difference between an activity being micro-cheating or harmless is the motivation of the person doing it. But sometimes the recipient doesn't know the intention of the person who has been in contact, so it can cause confusion and suspicion.
Take, for example, my friend Sam, who was sent a message on WhatsApp by a female friend that said simply: "I miss you!" As Sam had been friends, but nothing more, with this person for many years, he hadn't given it a second thought.
The problem was that his girlfriend didn't see it as innocent. She was furious.
While Sam eventually managed to persuade his girlfriend he wasn't cheating on her, the incident cast a shadow over their relationship for months.
It's hard to imagine such a scenario happening 15 years ago.
Before the explosion in online communication, Sam's friend would have had to either write a letter or telephone. Her motivation would have been far clearer.
But a one-line message has much greater potential for misunderstanding.
One of the issues the concept of micro-cheating highlights is that the line between what's friendly interaction and what might be considered unhealthy interest has become blurred.
In the past, a letter would have included enough detail to give a sense of the aim of the writer.
But micro-cheating can also serve a positive purpose. It can help strengthen the bonds between a couple.
Jealous reactions to suspected micro-cheating can actually help keep couples together, because they can prevent any acceleration in potential infidelity.
There are those who have criticised the idea of micro-cheating, saying that many of these interactions are the standard way of socialising online nowadays, and that promoting the idea they indicate cheating encourages people to distrust partners and stalk them online.
Yet the rise of social media, the increase in the use of emojis and the ambiguity of many posts and messages has increased the propensity for arguments.
What it does prove is that, in an age of openness and informality, more than ever we have to be watchful of how our actions are perceived by others. And it shows that we need to be honest with our partners about what is acceptable behaviour online.
Through the internet, we have quickly got used to interacting with strangers in a previously unheard-of, relaxed and informal way, but in terms of the history of human communication, all this is brand new. It's something we are still learning how to navigate.*
Some names have been changed.
Eyebrows were raised when the McRib began showing up on kiosks in-store.