19th June. So now, my love, I know the worst. Your brain is shrinking inside your skull. You are going to disintegrate very slowly, mind and body. You will feel our loving in rags and your God absent and I will hold you to my breast and cradle the shell of your skull, for you will have gone, my lover, my dear one. But not quite. But I am with you. I am your wife. We will see this illness as a journey we take together.' These are the first words Rebecca de Saintonge's wrote in her journal when her husband Jack was diagnosed with Lewy Body Dementia - an incurable degenerative brain disease. In the years that followed she faced the dual challenge of trying to keep the integrity of their relationship intact while avoiding her own destruction as their world gradually diminished. She survived by taking a lover. Through extracts from her journal, One Yellow Door explores the conflicting emotions and complex ethics of infidelity in marriage where one partner is severely disabled. It is about a re-thinking of traditional faith and the discovery of a new, deeper spirituality, and ultimately about the indestructibility of love.