1: IT'S MAKING YOU FAT
The 'partner pounds' theory is far from a myth. Studies have found that married men are more likely to be obese than men who have never been married or who are divorced. A 2012 review of 20 studies on relationships and weight found that "transitions into marriage were associated with weight gain, with transitions out of marriage associated with weight loss".
2: NAGGING CAN SHORTEN YOUR LIFE
Nagging can cut your life short - in particular for men. Frequent 'excessive demands' from partners more than double the risk of death in middle-aged men and increase it by 34 per cent in women, a 2014 Danish study found.
3: IT COULD BREAK YOUR HEART (LITERALLY)
All couples argue, but if it goes over the top, it can kill you. A study carried out by Michigan State University found a 34 per cent increase in heart problems in people who were involved in an unhappy relationship.
4: THOSE TEMPER TANTRUMS CAN KILL...
Psychologists followed 156 couples over 20 years to study how they reacted when asked to talk about issues in their relationship. Spouses who struggled to control their temper ran an 80 per cent greater risk of high blood pressure and cardiovascular problems.
5: ... BUT HOLDING BACK CAN BE A PAIN
The same study found that those who instead swallowed their anger were more prone to backache and muscle tension.
6: IT CAN WRECK YOUR IMMUNE SYSTEM
Half an hour of bickering can have a negative effect on your immune system. In a 1993 study of 90 newly-wed couples, those who had a 30-minute argument suffered a lowered immunological response in the following 24 hours.
7: YOU'LL BOTH HIT THE BOTTLE
A study in 2008 which followed 600 couples in their first four years of marriage found that if one had been a heavy drinker before the wedding, the other was likely to adopt their partner's drinking habits
8: BEING SINGLE CAN BE SOOTHING
Research published in the Journal Of Health And Social Behavior in 2003 found that single men and women had an overall better mental health than those who chose to remain in a turbulent relationship.
9: IT'S NOT BETTER TO HAVE LOVED AND LOST
Women who stay single throughout their lives have an overall better mental-health condition than women who have been in several relationships and have experienced break-ups and divorces, a UK study of more than 4,400 people found.
10: CREATES BAD BLOOD (FOR WOMEN ANYWAY)
Women experiencing 'marital stress' suffer similar effects on their overall physical health to women who are physically inactive or regular smokers, a 2009 US study found. These women had an increased risk of high blood pressure, abdominal obesity, high blood sugar and lower levels of 'good' cholesterol.