There are no rules for sex and intimacy. Partners should delight in whatever is mutually acceptable and which brings pleasure to each of them. In Sickness and in Health gives frank information about sexual practices including non-stressful positions and alternatives to intercourse such as oral sex and masturbation. In the book Lucille Carlton also confronts the issues of women's post-menopausal physical changes, impotence, and depression. She advocates open communication between partners and between couples and their doctors--since it's essential to understand the limitations of an infirmity and the potential side effects of medicine. She addresses the needs of both partners, the afflicted and their caregivers, and has a special chapter about being a senior single and survivorship.
The strengths that hold a marriage together in later years are those practiced earlier when both spouses are young and healthy--patience, honesty, humor, giving more than 50% and just not giving up. These are vital ingredients for lasting sexual intimacy. Both partners in a couple also need to understand that their ever-present need for touching, caring and love may be a crucial factor in coping with the challenge of chronic illness.