A quarter of Brits report some degree of unhappiness in their couple relationships, according to new research from OnePlusOne.

The findings, published in Understanding Relationship Quality, show that around 40% of people report being ‘very happy’ in their relationship, however around 15% are ‘very unhappy’ in their relationship. As a result, these partners are suffering from poor relationship quality.

Relationship quality generally declines over the course of a relationship, however the extent and speed of the decline can vary from couple to couple.

The study found that relationship quality can be affected by difficult events or circumstances such as becoming a parent, feeling pressure from work, being unemployed, caring for children with additional needs or having a partner who is unwell.

Dr Lester Coleman, head of research at OnePlusOne says: ‘The majority of what we know about the consequences of relationship breakdown originates from comparing people who are married to those who have divorced.

‘However, emerging research has paid increasing attention to the quality of the relationship and whether it differs across a range of family forms. These new studies have demonstrated that rather than relationship status, it is the quality of the relationship that matters.’