EWTN Catholic Q&A
Question from Joseph A. Apicella on 10-19-2017:

How do you explain celibacy to a non-Catholic ? I am sensitive enough not to say that it is better than marriage (The Catechism makes that clear). It's a choice. I get no help from Catholics who do not understand it.

Answer by David Gregson on 01-11-2018:

If a non-Catholic is a Bible-believer, perhaps you could refer him to what our Lord said in Matthew 19:12, "For there are eunuchs who have been so from birth, and there are eunuchs who have been made eunuchs by men, and there are eunuchs who have made themselves eunuchs for the sake of the kingdom of heaven. He who is able to receive this, let him receive it." This refers not to self-mutilation, but to a vow of celibacy.

Again, what St Paul wrote in I Corinthians 7, but especially verses 32-34, "The unmarried man is anxious about the affairs of the Lord, how to please the Lord; but the married man is anxious about worldly affairs, how to please his wife, and his interests are divided."

In short, one who is called to the priesthood, at least in the Western Church, is likely called to a life of undivided dedication to "the affairs of the Lord," which implies celibacy.