Celibacy in those who seek holiness is not limited to Catholics. The tradition is ancient in the Eastern church, where married men can become priests but priests cannot marry, and where bishops come from the unmarried clergy.
Hindu holy men do not marry, nor do most Buddist monks, for example. Gandhi, for example, was married but became celibate later in his life when he decided to become a holy man. Indeed, one legal reason for divorce in India is if one's husband leaves to become a holy man.
Many "mystery" cults that predate Christianity encouraged celibacy (mainly in the East.).
Some of this is due to the "gnostic" influence, which feels that bodily functions including sex, are evil, and only the spirit is good. Christianity rejected that idea, but some influence remained. And, of course, what Paul said stays true today: That a married man or woman has to use much of their time pleasing the spouse, but an unmarried person can do the Lord's work full time.
So I suppose we married schmucks are just out of luck when it comes to holiness?
Monks used to flagellate themselves too, in the name of holiness.
John Paul II has done more to counter the continuing influence of gnosticism in the Church than any Pope in history.