There is a growing body of research showing that cancer impacts upon the sexuality of informal carers in a couple relationship with a person with cancer. However, this research is primarily focused on partners of a person with gynaecological or breast cancer, within a framework where the physiological effects of cancer on sexual performance are the focus. We conducted semi-structured interviews with 20 informal carers in a couple relationship with a person with cancer, across a range of cancer types. The aim was to explore accounts of changes to sexuality and intimacy post-cancer, in the context of discursive constructions of sexuality and the caring role. Our findings show that partners’ sexual experiences were shaped by absence of desire in the person with cancer; the stress and exhaustion associated with caring tasks; the repositioning of the person with cancer as childlike or as an asexual ‘sick patient’; and the belief that there were expectations about ‘acceptable’ sexual conduct in the context of cancer caring. Carers accepted the diminishment of their sexual relationship, but expressed feelings of disappointment, anger and sadness about this loss. It is concluded that it is vital that support services are developed, so that couples may develop new sexual strategies, and cope more effectively with potential disruptions to their sexual and intimate relationship.