The physical changes that come with aging take place all over. And we do mean all over.
There are plenty of commercials singing the praises of various erectile dysfunction (ED) medications, but there are far fewer ads that talk about the sexual problems women face as they age.
As women reach their older years, the vagina actually shortens, and the vaginal walls thin and become less elastic. Vaginal secretions dry up, which can make any kind of penetration painful. In some women, the clitoris can become much more sensitive, making direct stimulation uncomfortable (note that this is not the case for every woman).
One solution: water-based lubricants. They're not sticky, they're easy to wash off and they can make vaginal intercourse much more pleasurable. Astroglide is an extremely popular brand.