First of all you need to realize that he is not meant to be single. Catholic celebacy was formed in the 10'th century.
Here an excerpt from a webiste that discusses the Celebacy of the Priests:
"Before the middle ages it was allowable for Catholic priests to have multiple wives and mistresses (concubines). But with concerns for protecting Church property from inheritance Pope Pelagius I made new priests agree offspring could not inherit Church property. Pope Gregory then declared all sons of priests illegitimate (only sons since lowly daughters could not inherit anyway in society).
In 1022 Pope Benedict VIII banned marriages and mistresses for priests and in 1139 Pope Innocent II voided all marriages of priests and all new priests had to divorce their wives. This had nothing to do with morality, multiple women for males had long been the norm since before biblical times, but it was about MONEY! In biblical times many wives, concubines and breeders was common and never spoken against other than by Paul to the Elders of Timothy and Titus."
You can read more: http://www.libchrist.com/bible/catholiccelibacy.ht...