Reasons given for these sudden break-ups included growing apart (22 per cent), having their eye on someone else (13 per cent)and feeling bored in and out of the bedroom (nine per cent).

Jo Hemmings, behavioural psychologist says: "After reaching the milestone of a year and half, bigger decisions start to loom for couples such as should they move in together and is this the person they want to spend the rest of their lives with.