Are UTI's only affiliated with having sex?

When you hear someone have a UTI why do people always think it's because of sex?Are UTI's only affiliated with having sex?
Not always. Older women and men get UTIs frequently due to not drinking enough water. Younger women get them all the time because of their shorter urethra.
It is not always associated with sexual activity, but in women it commonly is. That is why people make this association.
That is a common way of getting them although there are more. Certain drinks when consumed a lot can do it (dark colas for example), wiping the wrong way after urinating, bubble baths....there are many ways of getting them.