"Then some Pharisees came to him in order to test him. They asked, 'Is it lawful to divorce a wife for any cause?' He answered, 'Have you not read that from the beginning the Creator made them male and female, and said, ‘For this reason a man will leave his father and mother and will be united with his wife, and the two will become one flesh’? So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate.' They said to him, 'Why then did Moses command us to give a certificate of dismissal and to divorce her?' Jesus said to them, 'Moses permitted you to divorce your wives because of your hard hearts, but from the beginning it was not this way. Now I say to you that whoever divorces his wife, except for immorality, and marries another commits adultery.' The disciples said to him, 'If this is the case of a husband with a wife, it is better not to marry!' He said to them, 'Not everyone can accept this statement, except those to whom it has been given. for there are some eunuchs who were that way from birth, and some who were made eunuchs by others, and some who became eunuchs for the sake of the kingdom of heaven. The one who is able to accept this should accept it.'"
Being a man, I can assure you that the disciples' comment did not imply it is better to live a life of celibacy, but suggested that it would be better to just live with a woman rather than get married. But Jesus response was that unless you are a eunuch, any intimate relationship a man may have with a woman should be based on covenant. He left no room for the children of God to entertain casual, open-ended intimacy. If you desire a woman, then get married.
(1 Corinthians 7:2)
An intimate relationship is blessed by the marriage covenant instituted by God. Loose relations are selfish and uncommitted, affording the man and woman the ease of promiscuity and the convenience of leaving the relationship when things get tough. For the believer, marriage is trust, commitment, and perseverance that gain them the sanctification within the marriage. It is this symbolism that a believer is united to Christ, and without entering into this covenant, mere physically intimate relationships will have little, if any, reflection of the life of Christ in that relationship. Today, this does not appear to be the wisdom that the world is able to accept.
Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous. (Hebrews 13:4)