Josh 24 : 1 - 13,  Matt 19 : 3 - 12.Marriage is the highest expression of human love on earth. Indissolubity is the highest effect of marriage while divorce is the greatest tragedy of marriage. To avoid this the scriptures said that 'What God has joined together, let no man put asunder'. Agape love entails a lot of sacrifice and endurance and it is in marriage that this virtue is most tested. An unspiritual man /woman therefore, cannot live a successful married life. That is why, in the earliest New Testament  biblical times, ability to marry one wife and raise children successfully was a basic qualification for the priesthood - the presiding elders (presbyteroi) in the Eucharistic assembly of the time, Titus 1 : 6 - 11. 
The apostles, as soon as they understood this stringent requirement chose a better option - celibacy, as we find in today's gospel. But Christ explains further that the life of celibacy is a most unnatural one because 'it is not good for man to be alone', Gen 2 : 18. It requires some special grace from God. It is therefore only a few that have the grace for celibacy - eunuchs who have made themselves so for the sake of the kingdom of heaven. It requires dying to sin, Rom 6 : 11  and presenting one's body as a living sacrifice, Rom 12 : 1. St Paul recommended that those who cannot control their sexual urges should better go and marry a wife, 1 Cor 7 : 1 - 10.
Catholic priests and sisters are not "ordained  bachelors" /spinsters  as McGovern will call it who are running away from the obligations of marital commitment /responsibility but people who have a special vocation to dedicate their lives for the service of God in that special capacity. Many are quiting marriage and celibate life today because they lack the basic substractum for both spirituality which is sacrifice. When a Catholic priest, for example, resigns and goes into the married life just in order to be free, he will most likely be frustrated discovering that there is no such absolute freedom anywhere. He either made a mistake in discerning his true vocation or lacks the requisite discipline /sacrifice needed for both vocations. We need a lot of grace for both the marital and celibate life. May God bless you today!