In this period of time 24 and above are considerable. Well whatever might be the age the minimum age difference between a husband and a wife should be in between 10 - 20 years but that's not maintained.
Some people like living alone. The cause might be people are more interested in there lives they are living or they don't like to be dominant over someone. They might not want unusual pressures.
No, It's not a bad thing to get married.
Biology says that a sexual relationship is a must for a man to keep him fit but that's not essential for women.