Locking eyes with someone and letting the moment linger - does that count as flirting? How about exchanging compliments on each other’s Instagram photos?
And if flirting is defined as behaviour which suggests you are sexually attracted to someone - but stopping short of saying it outright – is it a form of cheating if you are spoken for?
This is a question that increasing numbers of people have been searching for the answer to in recent years, according to Google Trends. And the debate is also being fought out on social media.
To some, behaving flirtatiously – be that in person or on a device – is out-and-out wrong. If you are invested in your partner, your eyes shouldn’t wander.
For others, flirting is healthy and natural as long as it doesn’t lead to anything physical.
Yet, the answer can be easy to pin down if approached in the right way, explains Denise Knowles, a relationships counsellor at the charity Relate.
“I would never say flirting is cheating outright,” says Knowles. “It’s only when it starts to cause harm or the intention is to harm, or when you’re hiding - that’s when the betrayal happens and that can be very harmful," she told The Independent.
“If you’re having a chat and messing with someone, and it's understood from your side and their side that it’s just a bit of harmless fun and your partner also understands that, then you can enjoy it.
“But when you’re flirting and they are not sure of the boundaries or if your partner is unhappy with how you are behaving with other men and women and you continue to behave in that way, it can be very very harmful."
In this way, flirting or reactions to certain behaviours can be looked at as a symptom of the health of the relationship. And while flirting may now be easier – via text or in Snapchat photos – the principles of whether it is an issue are the same.
“If you’re trying to hide something there’s the element of betrayal," argues Knowles.
Someone worried or upset by their partner apparently flirting should not accuse them, but rather approach the situation with “curiosity” as they may not intend for their actions to be hurtful, says Knowles.
“I would question if you are snooping around," adds Knowles. "If you are snooping I would think ‘hang on is there something else going on?’ A lack of communication? Are you spending time apart? What can’t you talk to your partner about that is leading you to look at their phone?”
The bottom line is, explains Knowles: “If you are uncomfortable about anything in a relationship, or you’re suspicious, something is happening in your face, then you need to talk about it.
"And if it’s not easy to talk to your partner one to one then contact an organisation like relate can be really useful,” she advises.
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