It’s known as the honeymoon period, the first few years into marriage when couples are blissfully happy together.
The first three years of marriage of full of romance, surprises and devotion but after three and half years it all seems to go downhill.
Couples begin to stop making an effort with the simplest of tasks such as eating together, looking nice for one another and having deep conversations.
And instead of cuddling up on the couch or going to bed at the same time to rekindle their love in the bedroom, they will go to bed at different times.
This, as well as sitting in different rooms of the house and seeing friends more than each other, shows that couples will begin to take each other for granted after the three and a half year mark.
Kate Jones of Co-operative Food, which commissioned the study, said, “We all know that it's the little things that make a big difference, so adding a bit of quality time, like re-introducing 'date nights' or enjoying a meal in together, could be a good way to show you care.”
One of the biggest problems was couples failing to try and look nice for each other.
Most couples admitted to changing into pyjamas or tracksuit bottoms before their partner even came home.
Women said that they wouldn’t bother with make-up as much and favoured granny pants instead of matching underwear sets.
Men fell foul to leaving the bathroom door open when using it as well as committing one of the biggest bathroom faux pas – leaving the toilet set up.
After being together for so long, couples also admitted to forgetting major events such as birthdays, anniversaries and Valentine’s Day.
Despite all of this, two thirds of couples would still say they had a strong marriage a massive 90 per cent of people said they only do these things because they feel so comfortable with their partner.
Three quarters of couples even saw being taken for granted as a normal part of a long relationship.
Kate said, “Bad habits begin to creep into the relationship, such as breaking wind in front of each other, showering less, women forgetting to shave their legs, not closing the bathroom door when using the toilet and leaving the toilet seat up.
“Far from those bad habits being a sign that the relationship's on the rocks, it looks as though taking each other for granted can be a sign of security and comfort, and you don't need the reassurance of saying 'I love you' all the time.”
On a lighter note, 82 per cent of couples say that they have a happy marriage but 49 per cent did say they wish their partner would be more romantic.
Has the romance faded in your relationship? Let us know your thoughts by commenting below or tweeting us @FemaleFirst_UK