Sexual urges start from the age of puberty. There is no upper limit for the urges to decline. There is a popular myth that older people have a low sex drive. This is a folly. In fact, men in their 60s fathering children have been reported. This is impossible without sex.
In majority of cases, transient, more or less sex urges are reported. Humans are not robots and cannot have uniform sex urges in all situations and at all times. Availability of partner too may be an issue.
The easiest way of satisfying the sexual urges, if there is absence of partner or non-cooperative partner, is by indulging in self-masturbation. It is a healthy practice and carries no risk. There is no fear of unwanted pregnancy or STD.
If excess sexual thoughts are affecting daily lifestyles, visiting a doctor will help. Trying to focus on other activities like reading etc may help. The doctor may suggest some medications to reduce the sexual drive. These drugs are to be used under strict medical supervision, because unsolicited use may lead to myriads of problems.