This qualitative review explored the impact of dementia on marriage. The method was informed by systematic review and qualitative research methodologies. A comprehensive search of major databases was undertaken. The search identified 115 studies on the topic; 23 met the inclusion criteria and 19 were appraised as being of good methodological quality. Two major themes and five sub-themes emerged from the analysis of included studies, transition and loss. The theme of transition encompassed the three sub-themes of relationship, roles and intimacy and reflected the changes in the marriage and marital relationship that accompanied dementia. The theme of loss encompassed the two sub-themes of loss of a partner and loss of a marriage, which reflected the many losses that accompanied dementia. However, transition and loss were inter-related, because each change was accompanied by loss and each loss produced another change in the marriage.