Relational strain can be activated by cancer or the effects of its treatment, reducing couple communication and marital satisfaction over time, especially when sexual intimacy declines. Meta-analyses show a modest benefit from couple therapy, with some evidence suggesting better outcomes for couples where one or both partners have greater distress or cancer-related concerns. Presenting problems can include role or transition challenges, communication failure, loss of mutual consensus and conflict, boundary violations, fractures and frustration with sexuality or intimacy. Assessment of the couple includes understanding their experience of the oncology diagnosis and its treatment, their family-of-origin and relational background, coping styles, impact on communication, cohesion, and sexuality alongside any agendas they bring. Behavioral couple therapy strategies can facilitate constructive communication and problem solving to restore intimacy and connectedness during and after treatment. In the advanced cancer setting, existentially oriented models examine grief, death talk, caregiving, and preparation for dying. A search for continued meaning and purpose can empower the couple to live life out to the full, while also preparing for a good death and considering bereavement needs for the survivor.