_ Alzheimer's Disease and other Dementias Sex What Happens to Your Sex Life When Your Partner Develops Dementia? By article By Douglas Wornell MD What happens with sex in an established relationship -- perhaps one that’s been going on for decades -- when dementia enters the picture? At first glance, one might guess that the couple is likely older and sex isn’t happening anyway. Secondly, many may feel that the dementia will only push the couple further apart and therefore extinguish what glimmer of sexual activity was happening.