Katie Byrne: Bad marriages can cause serious harm to health, so why do people stay in them?
We've long heard about the benefits of a good marriage - lower cholesterol, better heart health and increased longevity, to name but a few.
But what about a bad marriage? Does it have a negative impact on a person's health in the same way a good marriage has a positive impact?
The answer, according to researchers at the universities of Nevada and Michigan, is an unequivocal yes. A bad marriage can seriously damage your health, they claim - and men are most at risk.
The researchers monitored 373 heterosexual couples over 16 years and found that frequent conflicts over trigger points like money, in-laws and leisure activities led to poorer health.
"We were surprised that conflict was more important for husbands' health than for wives' health," said study lead Rosie Shrout when she presented the preliminary results at the International Association for Relationship Research conference in Colorado.
This latest study on the health impacts of marriage is certainly provocative, but do we really need science to tell us that living in a conflict zone takes its toll? We've all seen the disillusionment and despair of a bad marriage just as we've seen the harmony and vibrancy of a good one.
The real question is why do couples choose to stay in marriages that have devolved into miserable, moribund relationships of convenience?
A bad marriage is mentally, physically and emotionally devastating, so what makes two unhappy people stay together when collective wisdom and scientific research tells them that they'd be better apart?
Here are just a few of the reasons people stay when they really should go.
I've invested 10 years…
When we irrationally follow through with a course of action simply because we have already invested in it, we fall into a thinking trap that psychologists call the 'sunk-cost bias'. Investors do it when they hold on to a stock they got in on early, even as it tumbles. Poker players do it when they keep betting on a low-strength hand simply because they raised pre-flop.
It's much the same in a bad marriage. Unhappy couples focus on the time they invested, the €2,000 they coughed up for relationship counselling and the many hours they spent plámásing the in-laws when, really, they should be thinking about folding their cards and minimising their losses.
We're staying together for the kids…
A 2015 poll of young people aged 18-22 who have experienced divorce found that 82pc of them would prefer their parents to part if they are unhappy. This is in stark contrast to the vast number of unhappy couples who believe they have to stay together 'for the sake of the children'.
Like it or not, you can't create a stable home environment when the atmosphere is tense, hostile and toxic. As for the unhappy couples who decide to stay together until the child is 18? They seem to be oblivious to the fact that at least one of them will be having an extra-marital affair at this point, and the other will have lost the will to live.
What will the neighbours say?
A number of studies have looked into the reasons why unhappy couples stay together and social embarrassment is cited with tedious regularity. Some couples feel under pressure to have a successful marriage; others fear the stigma of a 'failed marriage'.
Wedding day recollections compound the issue. Your friends and family have seen you dance to Whitney Houston's 'Greatest Love of All' and skip through a cornfield carrying heart-shaped balloons for your wedding album. Christ, you even wrote your own vows and read them out in front of 238 people.
The dread is that people will think you're fickle or foolish and, you're right, they probably will. For about five minutes. The truth, however, is that people are much too busy leading their own lives. And while your separation might feel like front page news, you're hardly Brad and Angelina.
But where will I live?
Of all the reasons people give for staying in an unhappy marriage, this one is probably the most legitimate. Even high-income families struggle to run two homes during a housing crisis - and most men would prefer to stay in a miserable marriage when their only other option is moving in with their mother.
Caught between a rock and a hard place, many couples stay together when the only thing they have in common is a mortgage and a health insurance plan.
They're trapped in a loveless marriage and while they give all sorts of reasons for staying together, they know, deep down, they can't afford to live apart.