A third of married people describe sex as a "chore" rather than an indulgence, research has found.
The study of 2000 married people found that sex is now ranked low in the priorities of modern relationships with a fifth confessing they often actively avoid the act.
The top reasons for avoiding time under the duvet with a partner were sheer fatigue, stress and work pressure and a general lack of satisfaction.
Worryingly, one in four went as far as to say sex was ‘boring’ and one in seven said they "would rather read a book".
The research, commissioned by UK health and wellbeing mutual organisation Benenden Healthcare Society, found sex is boring for one in four, and a fifth think their partner lacks the energy to make it satisfying.
"The strain of modern life is forcing married Brits to put their romantic lives on hold," Lawrence Christensen, Head of Communications & Strategy at Benenden Healthcare said.
"Married couples are finding that their priorities are elsewhere and this is down to a variety of reasons, but the important point is that this is causing worry and impacting on mental wellbeing.
"Sex isn't just the physical act but includes the expression of intimacy towards a partner and the statistics show that even then, Brits would rather read a book."
The average couple has sex just five times a month on average, however that's far removed from the ideal number – with respondents thinking 11 times a month the perfect amount for those married.
A resigned 10th of respondents say they just don't click with their partner in that way anymore. Sadly, one in 20 confess they just don’t think they love their partner anymore. In fact, one in four went as far as to say sex was "boring" and one in seven said they "would rather read a book".
Over a fifth said they have to feel their partner has shown them affection that day before they feel like it's an option, while a less constructive one in five have faked an illness rather than face getting intimate in the bedroom. Diet had a major impact on the sex lives of 43 percnt of respondents.
The majority of people said that their sex life inevitably faded after marriage – with the average married person saying the passion fades after just one year, eight months and 23 days.
One in 10 married people described their sex life as "non-existent" while four in 10 said it was "okay" – just a quarter could say they had a good sex life.
A third of married people find sex a chore and sadly 40 percent of the study claim they don't find their partner as attractive as they did when they first got married. Four in 10 think they and their partner are mismatched in terms of sex drive.
In fact, more than half of married people said problems or worries about their sex life have an impact on their life outside of the home, with many citing their work performance and temper with friends and colleagues as the main areas affected.
Three in ten Brits argue regularly about their sex life, and more than half admitted they have reason to worry.
A tenth of Brits worry they are failing their marriage because they don’t want sex, while a fifth say sex is not an important part of their marriage.
"Whilst a fifth of respondents say that sex is not an important part of marriage, many are finding that modern lifestyles are preventing a functioning sex life even when it is important to them," Lawrence Christensen.
"This is leading to worries and arguments and placing great mental strain on individuals. Is it time for married couples to reconsider their priorities?"