His 50th birthday was a big family celebration – but Joe* spent much of the party responding to work-related emails and checking Facebook.
The birthday boy's behaviour infuriated his wife, says psychologist Fergal Rooney.
"It had a significant impact on this social event and his wife was very annoyed, frustrated and embarrassed because she had to make excuses for him.
"She felt compromised and ashamed about what was a family occasion. It was quite a challenge to the relationship."
Joe, however, was utterly oblivious to the disapproval of his wife and family.
"He thought he was managing to engage in the family celebration and stay on top of work at the same time," says Fergal.
"He didn't see it as an issue that he was in and out of Facebook.
"This is one of the real difficulties that arise where couples have different perspectives on social media," says Fergal, who says there's a growing need for clarity between couples on the 'ground rules' for social media.
It was reported last that week that around 1.4 million Irish people now have access to a tablet – a 60pc jump in just six months – but there's also a downside.
Over the past few years relationship problems linked to social media use have landed with increasing frequency on Fergal's desk. He is the co-ordinator of the psychological services for healthy relationships and sexuality at St John of God's Hospital in Dublin's Stillorgan.
"We're seeing people whose relationships are in trouble or who are having difficulties maintaining a healthy relationship – and social media is a factor," he says.
Dating expert Feargal Harrington, who is a director of Intro matchmaking, says that the topic is increasingly cropping up in discussions with clients about failed relationships.
Up to 60pc of his company's clients in their 20s and 30s report that over-use of social media was a factor in the breakdown of a relationship.
"People tell us about the excessive time being spent on Facebook and Twitter either by themselves or their partners," says Feargal. "It means they weren't present in the relationship. Social media is a very big issue for lots of people."
Things get particularly sticky in a relationship, he says, when one partner objects to the stream of photographs and observations being uploaded by the other.
"There are people who simply do things to give the impression of the good life on Facebook.
"It's all about 'look at me now, and see how amazing my life is'. It's about one-upmanship."
But Feargal warns that while one partner or spouse may enjoy showing off, the other may feel uncomfortable at being 'tagged' or having photographs of themselves uploaded to Facebook, and a rift can develop.
There's also a growing mindset that a relationship is only as good as the Facebook photograph opportunities it creates – and the number of 'likes' and comments these attract, Feargal warns.
Social media increases the opportunities for infidelity, he says. Some people deliberately don't update their relationship status on Facebook when they become a couple, choosing instead to give the impression on social media that they're single and available.
"Your partner can be lying beside you quite literally flirting with someone who's not there," Feargal says.
One partner may be on a passworded page private-messaging somebody else. "They're lying beside each other in bed, on the phone, not talking, but pursuing other options – people are telling us their partners did this."
This can lead to a relationship breakdown.
"In my experience, it happens regularly," Feargal says. "Before you know it, your partner is running a secret life while lying next to you. We hear awful stories from people who feel they have been terribly betrayed."
Harrington was told about one long-term relationship that ended when a man discovered that his girlfriend had two Facebook pages. "She was flirting with different guys on the second page. When she was found out, she claimed she'd never met any of them and that this was okay because Facebook was not an online dating site."
The problem is that it all looks so very guileless, says Rena Maycock, co-director of Intro.
'You can 'innocently' approach someone you are interested in by 'commenting' on or 'liking' something they do. Whereas if you're in a bar or a club and make an approach to a person it's loaded with intent."
Social networking provides an anonymous secret forum for wannabe cheats, she believes.
"You can cheat to your heart's content in this virtual world with no consequences, and that's what is happening."
However, even genuinely innocuous overuse of social media by one partner can causes tension, resentment, jealousy and arguments in a relationship, psychologist Fergal Rooney warns.
""It can have an impact on trust," he says, pointing out that when one partner sees the other laughing at comments on Facebook, he or she may feel excluded.
"It's like he or she is not in the room. This can be very unsettling in a relationship where one person is feeling excluded and beginning to wonder what is going on," he says.
Communicating with an ex-lover on Facebook increases uncertainty and can lead to hostility, he warns:
"Emotions are upset, trust is impacted on and it has a silent, almost insidious affect on a relationship."
Couples can also be deceived by the false sense of 'togetherness' created by their use of social media.
Psychotherapist Bernadette Ryan says: "You may ask a couple how much time they spend together as a couple – but when you look into it you find that they're both on their laptops or tablets and are not, in fact, interacting at all.
"I know married couples who communicate with each other through Facebook," she adds.
"The problem is that some couples – often in their 30s – assume this is quality time together, but they're not connecting."
Social media may also cause difficulties if one spouse or partner is regularly spending much of their 'home time' on the laptop or smartphone, checking and sending work-related texts and emails.
"That has a potentially damaging effect on a relationship.
"It cuts the other person out and makes them feel they're not valued by that other person – it can ruin the emotional intimacy of a relationship," she says.
And if one partner regularly brings an internet-enabled device into bed, it can eat into a couple's sexual intimacy, Bernadette warns.
But that's not the end of it – for many people the phenomenon continues to cause problems following the break-up of their relationship.
"There is the temptation to go on to the ex-partner's page and check out what they are up to," she says.
"It prolongs the pain of relationship breakdown because you can see your ex moving on with their life and having a new relationship."
* Not his real name
Tonight at 8 pm, Fergal Rooney will be giving a public lecture entitled 'Insights and helpful hints on Managing the impact of social media on relationships'. The lecture which will take place at Saint John of God Hospital in Stillorgan in Dublin, is part of the hospital's free public lecture series.
'Instead of a chat after a film, he'd want to update his status'
Justine's relationship hit stormy waters after her boyfriend opened his first Facebook page and became obsessed with the social media site:
"He was constantly on his smartphone or laptop, checking his messages," she recalls.
He gradually developed separation anxiety, becoming noticeably restless if he wasn't able to check his messages often enough.
Eventually, she recalls, his fixation began to disrupt their quality 'couple time' – after a while they couldn't sit down and enjoy a DVD together.
"He couldn't focus on the film – he kept checking his messages.
"He'd go out with me to the cinema or to a restaurant and he was constantly checking the phone."
Once the film or the meal was over, she says, rather than chat with her about the evening they'd just spent together, her boyfriend would open his phone and start posting opinions about the film or the restaurant on Facebook.
Eventually, she says, the relationship broke down – "his addiction to social media was a factor in our break-up," she says.
* Not her real name
Tips for safeguarding your relationship
* Agree an evening watershed on the use of social media.
* Discuss the option of making meal-times technology-free.
* If issues are cropping up around social media use, sit down and address them.
* Recognise that your relationship must be a priority, and if your partner is unhappy with your use of social media, you must re-negotiate the situation.
* Ask yourself if you and your partner can sit down and enjoy one another's company without access to smart technology – or do you quickly become restless and dissatisfied?