doctors said she was no longer mentally capable of legally consenting to have sex .
when henry and donna lou rayhons married seven years ago in their northern iowa hometown , it was a second chance at love for the devoted couple , both previously widowed .
but their domestic routine of church activities and political functions unraveled as donna 's health began to fail .
last year , the 78-year-old woman was moved into a nursing home , suffering from dementia and alzheimers .