Why, because there is some chance that your spouse gets dementia? If the alternative is to be alone for the rest of your life, I'd take that chance.
To that point, from the article:
> The danger of isolation is well established. It tampers with the immune system and may be as detrimental to bodily health as lack of exercise and high blood pressure. One well-known study suggests that loneliness is comparable to smoking 15 cigarettes a day. We also know that loneliness raises the odds of depression and anxiety. Less well known is its effect on cognitive health: loneliness shortens attention span and interferes with judgment and self-control, the very attributes required to deal with a patient’s fixations and delusions.
To that point, from the article:
> The danger of isolation is well established. It tampers with the immune system and may be as detrimental to bodily health as lack of exercise and high blood pressure. One well-known study suggests that loneliness is comparable to smoking 15 cigarettes a day. We also know that loneliness raises the odds of depression and anxiety. Less well known is its effect on cognitive health: loneliness shortens attention span and interferes with judgment and self-control, the very attributes required to deal with a patient’s fixations and delusions.