Studies into decline in sexual activity among women in midlife produce equivocal findings, some implicating hormonal and physiological changes, others psycho-social and environmental factors. Women's perspectives rarely inform interpretation of the data. Associations between sexual satisfaction, activity and function, and health and lifestyle factors were explored using data from 2133 female participants in the third British National Survey of Sexual Attitudes and Lifestyles (2010-2012). Semi-structured interviews (2012-2015) with 23 women aged 45-59 reporting sexual dissatisfaction in Natsal-3 explored their perceptions of the influences on their sexual activity. Analysis of the survey data showed sexual dissatisfaction to be less common than low frequency and function. Neither menopausal stage nor age was independently associated with any of the dimensions of sexual experience. Only relationship unhappiness was independently associated with all three and communicational difficulty with two (dissatisfaction and lower function). In-depth interviews identified influences on sexual activity not captured in the survey. Tiredness attributed to contemporary challenges of midlife was a dominant theme. Relationship quality mediated its adverse impact. Sexual experience in midlife must be interpreted in light of both life-stage and era, notably, the increasing demands on women in contemporary society and their impact on vitality. Efforts to address sexual wellbeing should take account of the wider social context.