One in four older couples never make love - but most still say they couldn't be happier.
Trust, kindness, friendship and a sense of humour were all seen as more important in a relationship than sex, a survey of over-50s found.
A third of respondents said they made love at least once a week, with 2 per cent being intimate every day. But almost a quarter of those in long-term relationships said they had no sex at all.
Of these, just under half said they missed it, but the majority - 57 per cent - claimed to be perfectly happy without it.
Cari Rosen, editor of the website Gransnet which carried out the survey, said: "While passion is undoubtedly important for most people, it turns out that the glue in successful long-term relationships is compassion, kindness, generosity and friendship - which is advice that people of any age can use."
She added: "Lots of younger people don't like to think about older people having loving relationships and good sex, which is odd when you consider that for many of us it's the best case scenario."