Some singles just can't imagine being any other way. Suggest marriage and children and they might say something like "over my dead body". OK - we can deal with that.
For example, Chuck Simmins notes that you can get married after death.
But that's not the important question - far more people would be interested in sex after death. Have faith - according to no less an authority than Lily Tomlin, "There will be sex after death, we just will not be able to feel it."